Catch when dbus is unavailable (#522)

printrun/power/__init__.py

@@ -35,6 +35,9 @@ elif platform.system() == "Windows":
 else:
     import dbus
 
+    try:
+        bus = dbus.SessionBus()
+
         def inhibit_sleep(reason):
             if inhibit_sleep.handler is None:
                 bus = dbus.SessionBus()
@@ -57,6 +60,14 @@ else:
                 return
             inhibit_sleep.handler.UnInhibit(inhibit_sleep.token)
             inhibit_sleep.token = None
+    except dbus.DBusException, e:
+        print "dbus unavailable:", e.message
+
+        def inhibit_sleep(reason):
+            return
+
+        def deinhibit_sleep():
+            return
 
 try:
     import psutil