IRC: Only print first line of commit message

Otherwise, we print a whole bunch of lines, and with long commit messages,
we could cause an Excess Flood.

emily/out/irc.py

@@ -97,10 +97,14 @@ class IRC:
         push_msg += 'to the \x02{}\x02 branch:'.format(push['branch'])
 
         for commit in push['commits']:
+            try:
+                commit_msg = commit['msg'].splitlines()[0]
+            except IndexError:
+                commit_msg = commit['msg']
             msg = '{} ( {} ) by \x02{}\x02: {}'.format(commit['id'][:7],
                                                      commit['url'],
                                                      commit['author']['name'],
-                                                     commit['msg'])
+                                                     commit_msg)
             commit_msgs.append(msg)
 
             if len(commit_msgs) == 3 and count > 3: