Remove session bus from bus list

A session bus isn't being started so this hangs on startup.
diff --git a/rest-dbus b/rest-dbus
index 56ec1f9..ffaa0ed 100755
--- a/rest-dbus
+++ b/rest-dbus
@@ -8,7 +8,6 @@
 from xml.etree import ElementTree
 
 busses = {
-    'session': dbus.SessionBus,
     'system': dbus.SystemBus,
 }