relay: allow configuring custom relay server suffixes

Closes #333.

(cherry picked from commit 3900833458)

example-conf.yml

@@ -477,6 +477,10 @@ relay:
     # False.
     allow_clientbot_pms: false
 
+    # Sets the suffix that relay subservers should use. Defaults to "relay" (as in net1.relay,
+    # net2.relay, etc.) if not specified.
+    #server_suffix: "relay.yournet.net"
+
 games:
     # Sets the nick of the Games service, if you're using it. This defaults to "games" if not defined.
     nick: Games

plugins/relay.py

@@ -252,7 +252,10 @@ def spawnRelayServer(irc, remoteirc):
     try:
         # ENDBURST is delayed by 3 secs on supported IRCds to prevent
         # triggering join-flood protection and the like.
-        sid = irc.proto.spawnServer('%s.relay' % remoteirc.name,
+        suffix = conf.conf.get('relay', {}).get('server_suffix', 'relay')
+        # Strip any leading or trailing .'s
+        suffix = suffix.strip('.')
+        sid = irc.proto.spawnServer('%s.%s' % (remoteirc.name, suffix),
                                     desc="PyLink Relay network - %s" %
                                     (remoteirc.serverdata.get('netname')\
                                     or remoteirc.name), endburst_delay=3)