Give psusan and Uppity different SSH banner text.

'Uppity' is the name of a program that's only useful for debugging, so
I'd rather not have its name reused by psusan which I'm polishing up
to be actually useful to end users (if rather specialist ones).

So SshServerConfig now has an 'application name' field which is used
as the application name in the SSH banner, and Uppity sets it to
"Uppity" while psusan sets it to "PSUSAN".

sshserver.c

@@ -302,7 +302,7 @@ void ssh_server_start(Plug *plug, Socket *socket)
     srv->bpp = ssh_verstring_new(
         srv->conf, srv->logctx, srv->ssc->bare_connection,
         our_protoversion, &srv->version_receiver,
-        true, "Uppity");
+        true, srv->ssc->application_name);
     server_connect_bpp(srv);
     queue_idempotent_callback(&srv->bpp->ic_in_raw);
 }

sshserver.h

@@ -1,6 +1,7 @@
 typedef struct AuthPolicy AuthPolicy;
 
 struct SshServerConfig {
+    const char *application_name;
     const char *session_starting_dir;
 
     RSAKey *rsa_kex_key;

unix/uxpsusan.c

@@ -267,6 +267,7 @@ int main(int argc, char **argv)
 
     memset(&ssc, 0, sizeof(ssc));
 
+    ssc.application_name = "PSUSAN";
     ssc.session_starting_dir = getenv("HOME");
     ssc.bare_connection = true;
 

unix/uxserver.c

@@ -533,6 +533,7 @@ int main(int argc, char **argv)
 
     memset(&ssc, 0, sizeof(ssc));
 
+    ssc.application_name = "Uppity";
     ssc.session_starting_dir = getenv("HOME");
     ssc.ssh1_cipher_mask = SSH1_SUPPORTED_CIPHER_MASK;
     ssc.ssh1_allow_compression = true;