plugins: added new MissingModule exceptions to plugins using third party modules

src/plugins/plugin_adhoc_dbus.py

@@ -24,8 +24,11 @@ log = getLogger(__name__)
 from sat.core import exceptions
 from twisted.internet import defer
 from wokkel import data_form
-from lxml import etree
-from os import path
+try:
+    from lxml import etree
+except ImportError:
+    raise exceptions.MissingModule(u"Missing module lxml, please download/install it from http://lxml.de/")
+import os.path
 import uuid
 import dbus
 from dbus.mainloop.glib import DBusGMainLoop