Merge branch 'use-git-pull' into 'master'

Use git pull if the repository exists

Use git pull if the repository exists, this is more error proof and sufficient since the ce and ee repositories are huge.

See merge request !39

generate.rb

@@ -31,8 +31,12 @@ def main
     tmp_dir = File.join('/tmp/gitlab', relative_path)
     unless 'no-clone' == ARGV[0]
-      system("rm -rf #{tmp_dir}")
-      system("git clone #{ENV['PROGRESS'] ? nil : '--quiet'} -- #{clone_url} #{tmp_dir}")
+      if File.exist?("#{tmp_dir}/.git/config")
+        system("git -C #{tmp_dir} #{ENV['PROGRESS'] ? nil : '--quiet'} pull")
+      else
+        system("rm -rf #{tmp_dir}")
+        system("git clone #{ENV['PROGRESS'] ? nil : '--quiet'} -- #{clone_url} #{tmp_dir}")
+      end
     end
     $progress.puts 'Deleting files that should be excluded'