Detect values of None in utils.get_irc()

The intent for the get_irc() function is to return an empty string
when no nick is found, but the API tends to provide a null (None)
value explicitly. When this happens, convert it to the empty string
too.

Change-Id: I9b62b1d722136246d1987a1a45ca771bdc02579c

openstack_election/utils.py

@@ -178,6 +178,9 @@ def get_irc(member, filepath=None):
     member_data = member.get('data', [])
     if member_data:
         irc = member_data[0].get('irc', '')
+        # The API can return None for nonexistent nicks
+        if irc is None:
+            irc = ''
     return irc