[dm] define an exception we use. Fixes #5457

src/common/dbus_support.py

@@ -63,7 +63,7 @@ class SystemBus:
 			raise exceptions.DbusNotSupported
 
 		if not self.present():
-				raise exceptions.SystemBusNotPresent
+			raise exceptions.SystemBusNotPresent
 		return self.system_bus
 
 	def bus(self):

src/common/exceptions.py

@@ -75,7 +75,20 @@ class SessionBusNotPresent(Exception):
 		Exception.__init__(self)
 
 	def __str__(self):
-		return _('Session bus is not available.\nTry reading http://trac.gajim.org/wiki/GajimDBus')
+		return _('Session bus is not available.\nTry reading %(url)s') % \
+			{'url': 'http://trac.gajim.org/wiki/GajimDBus'}
+
+class SystemBusNotPresent(Exception):
+	"""
+	This exception indicates that there is no session daemon
+	"""
+
+	def __init__(self):
+		Exception.__init__(self)
+
+	def __str__(self):
+		return _('System bus is not available.\nTry reading %(url)s') % \
+			{'url': 'http://trac.gajim.org/wiki/GajimDBus'}
 
 class NegotiationError(Exception):
 	"""