Update Poltergeist: the version 1.5 requires PhantomJS 1.8 which isn't even available in Homebrew now

Gemfile

@@ -40,7 +40,7 @@ end
 group :test do
   gem 'shoulda-matchers', '~> 1.0.0'
   gem 'capybara', '~> 2.2.1'
-  gem 'poltergeist', '~> 1.5.0'
+  gem 'poltergeist', '~> 1.10.0'
   gem 'database_cleaner', '~> 1.2.0'
   gem 'launchy', '~> 2.4.2'
   gem 'spork', '~> 0.9.2'

Gemfile.lock

@@ -159,10 +159,9 @@ GEM
       mime-types
       mimemagic (= 0.3.0)
     pg (0.17.1)
-    poltergeist (1.5.1)
+    poltergeist (1.10.0)
       capybara (~> 2.1)
       cliver (~> 0.3.1)
-      multi_json (~> 1.0)
       websocket-driver (>= 0.2.0)
     polyglot (0.3.5)
     pry (0.9.12.6)
@@ -238,7 +237,7 @@ GEM
       json (>= 1.8.0)
     warden (1.1.1)
       rack (>= 1.0)
-    websocket-driver (0.6.3)
+    websocket-driver (0.6.5)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.2)
     will_paginate (3.0.7)
@@ -273,7 +272,7 @@ DEPENDENCIES
   netzke-core (~> 0.8.0)
   paperclip (~> 4.3)
   pg (~> 0.17.1)
-  poltergeist (~> 1.5.0)
+  poltergeist (~> 1.10.0)
   pry (~> 0.9.8)
   rails (= 3.2.13)
   rake (< 11.0)