Should no longer freak out when omniauth settings aren't present in
gitlab.yml. People who aren't using it shouldn't even have to put a
'false' entry in their config for it (and probably wouldn't, after an
upgrade).

Merge branch 'master' into non-interactive-aws-install

Conflicts:
	doc/installation.md

Fix merge mess in installation.md

New config option: git_hooks_path

Closes #1237

of 'gitlab.yml'.

gitlabhq\config\initializers\1_settings.rb looks for
'gitolite_admin_uri' in the 'git' section of 'gitlab.yml'

Actually, that setting is in the 'git_host' section.
If not fixed, the 'gitolite_admin_uri' would always be equals to
'git@localhost:gitolite-admin', even if the administrator wants
to have another user than 'git' in charge of that repo.