Bug 1388082 - Remove unused import. r=automatedtester

MozReview-Commit-ID: 1W6eI99Ze40

--HG--
extra : rebase_source : 277fe9280e71db8afff5ad3a588e2155d589adf8

testing/marionette/message.js

@@ -7,7 +7,6 @@
 var {utils: Cu} = Components;
 
 Cu.import("resource://gre/modules/Log.jsm");
-Cu.import("resource://gre/modules/Task.jsm");
 
 Cu.import("chrome://marionette/content/assert.js");
 Cu.import("chrome://marionette/content/error.js");