Implement Simon's suggestion of moving DEFAULT_PROTOCOL into a per-backend-

link-module const variable `be_default_protocol' which suggests a sensible
default to the front end (which can ignore it). (DEFAULT_PORT is replaced by a
lookup in the backend[] table.)
Still not pretty, but it does mean that the recent fix for `ssh-default'
doesn't break PuTTYtel.

[originally from svn r2613]

be_nossh.c

@@ -7,6 +7,8 @@
 #include <stdio.h>
 #include "putty.h"
 
+const int be_default_protocol = PROT_TELNET;
+
 struct backend_list backends[] = {
     {PROT_TELNET, "telnet", &telnet_backend},
     {PROT_RLOGIN, "rlogin", &rlogin_backend},