Fix create repo

Created by: jouve

Hello,

this request fixes #1257.

This bug happens because gitolite does not create the bare repository in /home/git/repositories if we only add the repo line to the gitolite.conf file. It also need a line with rights + key. ex, just adding :

repo    toto

gitolite won't create the repository but with :

repo    toto
  RW+    = somekey

gitolite will create a bare repository : /home/git/repositories/toto.git.

If a user creates a repo and he has no ssh key, the first case apply, gitolite does not create a repo and of course gitlab can't see the post-receive file. To fix that, we must add a default key to the repo.

First commit does this by adding gitlab's key with RW+ rights to each repo. This is not a problem because gitlab is already admin of all repos.

Second commit provide a task to fix existing repositories.