Add enterprise linux distributions as officially supported.
Some people are getting the error 'The remote end hung up unexpectedly' due to large chuncks.
Update changelog.
 Merge branch 'increase-nginx-push-size' into 'master'

Increase Nginx Push Size
 Merge branch 'add-enterprise-linux' into 'master'

Add Enterprise Linux
Merge branch 'master' of dev.gitlab.org:gitlab/gitlabhq
Merge branch 'master' of github.com:gitlabhq/gitlabhq