we can receive empty message (for ex for gc_subjects)

src/common/connection.py

@@ -177,8 +177,6 @@ class Connection:
 	def _messageCB(self, con, msg):
 		"""Called when we recieve a message"""
 		msgtxt = msg.getBody()
-		if not msgtxt: # empty message
-			return
 		mtype = msg.getType()
 		tim = msg.getTimestamp()
 		tim = time.strptime(tim, '%Y%m%dT%H:%M:%S')
@@ -207,9 +205,13 @@ class Connection:
 			if subject:
 				self.dispatch('GC_SUBJECT', (str(msg.getFrom()), subject))
 			else:
+				if not msgtxt: # empty message
+					return
 				self.dispatch('GC_MSG', (str(msg.getFrom()), msgtxt, tim))
 				gajim.logger.write('gc', msgtxt, str(msg.getFrom()), tim = tim)
 		else:
+			if not msgtxt: # empty message
+				return
 			gajim.logger.write('incoming', msgtxt, str(msg.getFrom()), tim = tim)
 			self.dispatch('MSG', (str(msg.getFrom()), msgtxt, tim))
 	# END messageCB