Merge branch 'gitaly-fsck-mandatory' into 'master'

Make 'git fsck' mandatory

See merge request gitlab-org/gitlab-ce!17648

lib/gitlab/git/repository.rb

@@ -1189,15 +1189,9 @@ module Gitlab
       end
 
       def fsck
-        gitaly_migrate(:git_fsck) do |is_enabled|
-          msg, status = if is_enabled
-                          gitaly_fsck
-                        else
-                          shell_fsck
-                        end
+        msg, status = gitaly_repository_client.fsck
 
-          raise GitError.new("Could not fsck repository: #{msg}") unless status.zero?
-        end
+        raise GitError.new("Could not fsck repository: #{msg}") unless status.zero?
       end
 
       def create_from_bundle(bundle_path)
@@ -1596,14 +1590,6 @@ module Gitlab
         File.write(File.join(worktree_info_path, 'sparse-checkout'), files)
       end
 
-      def gitaly_fsck
-        gitaly_repository_client.fsck
-      end
-
-      def shell_fsck
-        run_git(%W[--git-dir=#{path} fsck], nice: true)
-      end
-
       def rugged_fetch_source_branch(source_repository, source_branch, local_ref)
         with_repo_branch_commit(source_repository, source_branch) do |commit|
           if commit