Update bootstrap-sass

Gemfile

@@ -119,7 +119,7 @@ group :assets do
   gem "jquery-ui-rails",  "2.0.2"
   gem "modernizr",        "2.6.2"
   gem "raphael-rails",    git: "https://github.com/gitlabhq/raphael-rails.git"
-  gem 'bootstrap-sass',   "2.2.1.1"
+  gem 'bootstrap-sass'
   gem "font-awesome-sass-rails", "~> 3.0.0"
   gem "gemoji", "~> 1.2.1", require: 'emoji/railtie'
   gem "gon"

Gemfile.lock

@@ -64,7 +64,7 @@ GEM
       erubis (>= 2.6.6)
     binding_of_caller (0.7.1)
       debug_inspector (>= 0.0.1)
-    bootstrap-sass (2.2.1.1)
+    bootstrap-sass (2.3.1.0)
       sass (~> 3.2)
     builder (3.0.4)
     capybara (2.1.0)
@@ -398,7 +398,7 @@ GEM
     rubyntlm (0.1.1)
     sanitize (2.0.3)
       nokogiri (>= 1.4.4, < 1.6)
-    sass (3.2.8)
+    sass (3.2.9)
     sass-rails (3.2.6)
       railties (~> 3.2.0)
       sass (>= 3.1.10)
@@ -507,7 +507,7 @@ DEPENDENCIES
   awesome_print
   better_errors
   binding_of_caller
-  bootstrap-sass (= 2.2.1.1)
+  bootstrap-sass
   capybara
   carrierwave
   chosen-rails (= 0.9.8)