fix problem in conversations#index

I think the problem that we were getting was because
we added guard-gulp to our development gemfile
and it maybe require's mkmf, which adds the
.with_config scope.

test plan:
* go to conversations in dev mode, it should work
* run `bundle exec guard`, it should work
* with guard running, change a coffee/js file
* guard should see the change and regenerate the appropriate file
  and you should see gulp 'rev' run.

Change-Id: Ia43e9436e19b32eb3959f6f2d9c2d8d7674aa109
Reviewed-on: https://gerrit.instructure.com/57777
Reviewed-by: Jacob Fugal <jacob@instructure.com>
Reviewed-by: Matthew Wheeler <mwheeler@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins
Product-Review: Ryan Shaw <ryan@instructure.com>
QA-Review: Ryan Shaw <ryan@instructure.com>

Gemfile.d/development.rb

@@ -1,6 +1,6 @@
 group :development do
   gem 'guard', '1.8.0'
-  gem 'guard-gulp'
+  gem 'guard-gulp', '~>0.0.2', require: false
   gem 'listen', '~>1.3' # pinned to fix guard error
   gem 'rb-inotify', '~>0.9.0', require: false
   gem 'rb-fsevent', require: false

Guardfile

@@ -1,4 +1,5 @@
 $LOAD_PATH << File.dirname(__FILE__)
+require 'guard-gulp'
 
 ignore! Listen::DirectoryRecord::DEFAULT_IGNORED_DIRECTORIES - ['vendor'] + [%r{vendor/(?!plugins)}]