Revert "Update poltergeist to support phantomjs 2.0"

This reverts commit d70126c1fb.

Gemfile

@@ -252,7 +252,7 @@ group :development, :test do
   gem 'rb-inotify', require: linux_only('rb-inotify')
 
   # PhantomJS driver for Capybara
-  gem 'poltergeist', '~> 1.6.0'
+  gem 'poltergeist', '~> 1.5.1'
 
   gem 'jasmine', '2.0.2'
 

Gemfile.lock

@@ -392,7 +392,7 @@ GEM
       ast (>= 1.1, < 3.0)
     pg (0.15.1)
     phantomjs (1.9.2.0)
-    poltergeist (1.6.0)
+    poltergeist (1.5.1)
       capybara (~> 2.1)
       cliver (~> 0.3.1)
       multi_json (~> 1.0)
@@ -650,9 +650,7 @@ GEM
     webmock (1.16.0)
       addressable (>= 2.2.7)
       crack (>= 0.3.2)
-    websocket-driver (0.5.3)
-      websocket-extensions (>= 0.1.0)
-    websocket-extensions (0.1.2)
+    websocket-driver (0.3.3)
     wikicloth (0.8.1)
       builder
       expression_parser
@@ -746,7 +744,7 @@ DEPENDENCIES
   omniauth-twitter
   org-ruby (= 0.9.12)
   pg
-  poltergeist (~> 1.6.0)
+  poltergeist (~> 1.5.1)
   pry-rails
   quiet_assets (~> 1.0.1)
   rack-attack