Free topic array on channel deletion.

The topic array in the CHANNEL structure must be free()'d before the
channel itself becomes deleted.

(backport of commit 18efc7469c of master branch)

src/ngircd/channel.c

@@ -1027,9 +1027,9 @@ Delete_Channel( CHANNEL *Chan )
 
 	Log( LOG_DEBUG, "Freed channel structure for \"%s\".", Chan->name );
 
-	/* Invite- und Ban-Lists aufraeumen */
-	Lists_Free( &chan->list_bans );
-	Lists_Free( &chan->list_invites );
+	array_free(&chan->topic);
+	Lists_Free(&chan->list_bans);
+	Lists_Free(&chan->list_invites);
 
 	/* Neu verketten und freigeben */
 	if( last_chan ) last_chan->next = chan->next;