master: Don't include imap-hibernate when counting auth's max client_…

…limit

imap-hibernate doesn't do any auth connections, so it doesn't need it.
It's a bit ugly to add an explicit service name comparison here, but
there didn't really seem to be many other good choices:

 * Could have removed protocol=imap from imap-hibernate. I was close to
doing this, but maybe it's better that imap-only processes would have
their protocol set to "imap".

 * Could have added a new service type, but seems pretty unnecessary to add
some kind of a "nonauth" just for this. A reverse "needs-auth" might have
been ok though.

Perhaps in future we'll implement proper dependencies across services and
those dependencies could be used to calculate this limit more precisely.

src/master/master-settings.c

@@ -574,9 +574,11 @@ master_settings_verify(void *_set, pool_t pool, const char **error_r)
 
 		if (*service->protocol != '\0') {
 			/* each imap/pop3/lmtp process can use up a connection,
-			   although if service_count=1 it's only temporary */
-			if (service->service_count != 1 ||
-			    strcmp(service->type, "login") == 0)
+			   although if service_count=1 it's only temporary.
+			   imap-hibernate doesn't do any auth lookups. */
+			if ((service->service_count != 1 ||
+			     strcmp(service->type, "login") == 0) &&
+			    strcmp(service->name, "imap-hibernate") != 0)
 				max_auth_client_processes += process_limit;
 		}
 		if (strcmp(service->type, "login") == 0 ||