Improve diff and bump gitlab_git revision

Gemfile

@@ -31,7 +31,8 @@ gem 'omniauth-shibboleth'
 # Extracting information from a git repository
 # Provide access to Gitlab::Git library
-gem "gitlab_git", '~> 6.0', git: 'https://gitlab.com/gitlab-org/gitlab_git.git', ref: 'c405e4cf147fc5f7b9eae8aabaf3bee695eb2832'
+# gem "gitlab_git", '~> 6.0', path: '../../gitlab_git'
+gem "gitlab_git", '~> 6.0', git: 'https://gitlab.com/gitlab-org/gitlab_git.git', ref: 'fab781735c1ab2a8f1dc2fda33b169af99ec7e2e'
 # Ruby/Rack Git Smart-HTTP Server Handler
 gem 'gitlab-grack', '~> 2.0.0.pre', require: 'grack'

Gemfile.lock

 GIT
   remote: https://gitlab.com/gitlab-org/gitlab_git.git
-  revision: c405e4cf147fc5f7b9eae8aabaf3bee695eb2832
-  ref: c405e4cf147fc5f7b9eae8aabaf3bee695eb2832
+  revision: fab781735c1ab2a8f1dc2fda33b169af99ec7e2e
+  ref: fab781735c1ab2a8f1dc2fda33b169af99ec7e2e
   specs:
     gitlab_git (6.3.0)
       activesupport (~> 4.0)

lib/gitlab/diff/parser.rb

@@ -13,7 +13,7 @@ module Gitlab
         lines_arr = ::Gitlab::InlineDiff.processing lines
-        lines_arr.each do |line|
+        lines_arr.drop(4).each do |line|
           raw_line = line.dup
           next if filename?(line)