Stop Fail500 and LogError from panicing with nil request or error

Closes #99

See merge request !156

Use test helpers in main_test.go

See merge request !153

Gitaly cleanup

See merge request !152

Version 1.4.3

See merge request !151

Support insecure TCP connections to Gitaly

See merge request !150

Forward {upload,receive}-pack requests to Gitaly

Closes gitaly#125

See merge request !143

Closes gitlab-org/gitaly#125

Pass full Gitaly 'Repository' message on from Rails

See merge request !147

We are in the middle of making the Gitaly 'Repository' message contain
more fields than it used to. This change makes sure that workhorse
automatically passes through the new message format (as long as the
gitaly client versions in gitlab-rails and workhorse match).

Version 1.4.2

See merge request !146

Return error 500, if possible, from GET /info/refs

Closes #121

See merge request !145

Update Redis references in README

See merge request !142

Version 1.4.1

See merge request !141

Redis fixes

Closes #117 and #114

See merge request !140

The redigomock package is GPLv2. Because I am unsure if this is
compatible with our own license and because we will have the GitLab
9.0 release soon I am adding this hack to keep redigomock in our test
suite but out of our sources.

Also: https://gitlab.com/gitlab-org/gitlab-workhorse/issues/114

Bug-fix for redis connection

See merge request !137