Merge branch 'fix-archive-corrupt' into 'master'

Fix archive corruption

* When I click download I trigger archive creation
* We don't use tmp storage for uncompleted archive
* When I refresh a page - archiving still in progress but file already exists - I get corrupted (unfinished) file
* If I wait for few more seconds and click download - I get correct file because archiving operation finished and file is valid

This MR fixes issue by bumping `gitlab_git` to newer version. In this version archive created in tmp file and becomes available only when archive operation finished.

Fixes #1394

See merge request !954

Gemfile.lock

@@ -175,7 +175,7 @@ GEM
       mime-types (~> 1.19)
     gitlab_emoji (0.0.1.1)
       emoji (~> 1.0.1)
-    gitlab_git (6.0.0)
+    gitlab_git (6.0.1)
       activesupport (~> 4.0)
       charlock_holmes (~> 0.6)
       gitlab-grit (~> 2.6)
@@ -282,7 +282,7 @@ GEM
     method_source (0.8.2)
     mime-types (1.25.1)
     mini_portile (0.6.0)
-    minitest (5.3.4)
+    minitest (5.3.5)
     multi_json (1.10.1)
     multi_xml (0.5.5)
     multipart-post (1.2.0)