Remove some ancient cruft from the FAQ.

- I haven't heard of OpenSSH/OpenSSL mismatches being a common problem
   for a long time. Specific advice about OpenSSH 3.1/3.4 seems unlikely
   to be useful these days.
 - "Incorrect MAC received on packet" doesn't seem to be a common
   problem these days, and if anyone encounters it, the words in the
   "Errors" bit of the docs seem adequate without a FAQ entry as well.

doc/errors.but

@@ -122,9 +122,7 @@ ridiculous amount of memory, and will terminate with an \q{Out of
 memory} error.
 
 This can happen in SSH-2, if PuTTY and the server have not enabled
-encryption in the same way (see \k{faq-outofmem} in the FAQ). Some
+encryption in the same way (see \k{faq-outofmem} in the FAQ).
-versions of \i{OpenSSH} have a known problem with this: see
-\k{faq-openssh-bad-openssl}.
 
 This can also happen in PSCP or PSFTP, if your \i{login scripts} on the
 server generate output: the client program will be expecting an SFTP
@@ -233,8 +231,13 @@ protection (such as HTTP) will manifest in more subtle failures (such
 as misdisplayed text or images in a web browser) which may not be
 noticed.
 
-A known server problem which can cause this error is described in
+Occasionally this has been caused by server bugs. An example is the
-\k{faq-openssh-bad-openssl} in the FAQ.
+bug described at \k{config-ssh-bug-hmac2}, although you're very
+unlikely to encounter that one these days. 
+
+In this context MAC stands for \ii{Message Authentication Code}. It's a
+cryptographic term, and it has nothing at all to do with Ethernet
+MAC (Media Access Control) addresses, or with the Apple computer.
 
 \H{errors-garbled} \q{Incoming packet was garbled on decryption}
 
@@ -249,9 +252,6 @@ the setting of \q{Miscomputes SSH-2 encryption keys} (see
 \k{config-ssh-bug-derivekey2}) or \q{Ignores SSH-2 maximum packet
 size} (see \k{config-ssh-bug-maxpkt2}) on the Bugs panel.
 
-Another known server problem which can cause this error is described
-in \k{faq-openssh-bad-openssl} in the FAQ.
-
 \H{errors-x11-proxy} \q{PuTTY X11 proxy: \e{various errors}}
 
 This family of errors are reported when PuTTY is doing X forwarding.

doc/faq.but

@@ -601,34 +601,6 @@ documentation.)
 
 \H{faq-trouble} Troubleshooting
 
-\S{faq-incorrect-mac}{Question} Why do I see \q{Incorrect MAC
-received on packet}?
-
-One possible cause of this that used to be common is a bug in old
-SSH-2 servers distributed by \cw{ssh.com}. (This is not the only
-possible cause; see \k{errors-crc} in the documentation.)
-Version 2.3.0 and below of their SSH-2 server
-constructs Message Authentication Codes in the wrong way, and
-expects the client to construct them in the same wrong way. PuTTY
-constructs the MACs correctly by default, and hence these old
-servers will fail to work with it.
-
-If you are using PuTTY version 0.52 or better, this should work
-automatically: PuTTY should detect the buggy servers from their
-version number announcement, and automatically start to construct
-its MACs in the same incorrect manner as they do, so it will be able
-to work with them.
-
-If you are using PuTTY version 0.51 or below, you can enable the
-workaround by going to the SSH panel and ticking the box labelled
-\q{Imitate SSH2 MAC bug}. It's possible that you might have to do
-this with 0.52 as well, if a buggy server exists that PuTTY doesn't
-know about.
-
-In this context MAC stands for \ii{Message Authentication Code}. It's a
-cryptographic term, and it has nothing at all to do with Ethernet
-MAC (Media Access Control) addresses.
-
 \S{faq-pscp-protocol}{Question} Why do I see \q{Fatal: Protocol
 error: Expected control record} in PSCP?
 
@@ -895,41 +867,6 @@ You should still read the
 page} on the PuTTY website (also provided as \k{feedback} in the
 manual), and follow the guidelines contained in that.
 
-\S{faq-openssh-bad-openssl}{Question} Since my SSH server was upgraded
-to \i{OpenSSH} 3.1p1/3.4p1, I can no longer connect with PuTTY.
-
-There is a known problem when OpenSSH has been built against an
-incorrect version of OpenSSL; the quick workaround is to configure
-PuTTY to use SSH protocol 2 and the Blowfish cipher.
-
-For more details and OpenSSH patches, see
-\W{http://bugzilla.mindrot.org/show_bug.cgi?id=138}{bug 138} in the
-OpenSSH BTS.
-
-This is not a PuTTY-specific problem; if you try to connect with
-another client you'll likely have similar problems. (Although PuTTY's
-default cipher differs from many other clients.)
-
-\e{OpenSSH 3.1p1:} configurations known to be broken (and symptoms):
-
-\b SSH-2 with AES cipher (PuTTY says \q{Assertion failed! Expression:
-(len & 15) == 0} in \cw{sshaes.c}, or \q{Out of memory}, or crashes)
-
-\b SSH-2 with 3DES (PuTTY says \q{Incorrect MAC received on packet})
-
-\b SSH-1 with Blowfish (PuTTY says \q{Incorrect CRC received on
-packet})
-
-\b SSH-1 with 3DES
-
-\e{OpenSSH 3.4p1:} as of 3.4p1, only the problem with SSH-1 and
-Blowfish remains. Rebuild your server, apply the patch linked to from
-bug 138 above, or use another cipher (e.g., 3DES) instead.
-
-\e{Other versions:} we occasionally get reports of the same symptom
-and workarounds with older versions of OpenSSH, although it's not
-clear the underlying cause is the same.
-
 \S{faq-ssh2key-ssh1conn}{Question} Why do I see \q{Couldn't load
 private key from ...}? Why can PuTTYgen load my key but not PuTTY?