Bug 1270357 Add isDeeply to mochitest eslintrc r=kmag

MozReview-Commit-ID: 6TsspFtPiuZ

--HG--
extra : rebase_source : 620297cd519fc394ac2877f2c5e5b2018791aa56

testing/mochitest/mochitest.eslintrc

@@ -21,6 +21,7 @@
     "gTestPath": false,
     "info": false,
     "is": false,
+    "isDeeply": false,
     "isnot": false,
     "ok": false,
     "promise": false,