prevent TB for invalid keyword in send_message

add SystemBus initialisation in try:
to catch cases when system bus is not present

src/common/zeroconf/connection_zeroconf.py

@@ -270,7 +270,8 @@ class ConnectionZeroconf(ConnectionHandlersZeroconf):
 		return STATUS_LIST[self.connected]
 
 	def send_message(self, jid, msg, keyID, type = 'chat', subject='',
-	chatstate = None, msg_id = None, composing_jep = None, resource = None):
+	chatstate = None, msg_id = None, composing_jep = None, resource = None, 
+	user_nick = None):
 		print 'connection_zeroconf.py: send_message'
 
 		fjid = jid

src/common/zeroconf/zeroconf.py

@@ -223,8 +223,8 @@ class Zeroconf:
 
 	# connect to dbus
 	def connect(self):
-		self.bus = dbus.SystemBus()
 		try:
+			self.bus = dbus.SystemBus()
 			# is there any way to check, if a dbus name exists?
 			# that might make the Introspect Error go away...
 			self.server = dbus.Interface(self.bus.get_object(avahi.DBUS_NAME, \