fix(dependency): Mongoose 4.4.7 bug

Fixes an issue with Mongoose `4.4.7` that causes the database
connection.db property to be undefined. This issue is causing our builds
to fail.

Sets the Mongoose version to `~4.4.3 <4.4.7` for now until we
investigate further. This should solve the issue of our failing builds,
when the `dropdb` Grunt/Gulp task is ran with the E2E tests.

package.json

@@ -47,7 +47,7 @@
     "method-override": "~2.3.5",
     "gulp-wiredep": "~0.0.0",
     "mocha": "~2.4.5",
-    "mongoose": "~4.4.3",
+    "mongoose": "~4.4.3 <4.4.7",
     "morgan": "~1.6.1",
     "multer": "~1.1.0",
     "nodemailer": "~2.1.0",