Disable git hooks for git-annex pushes

Customer in https://gitlab.zendesk.com/agent/tickets/7394 suggested disabling git hooks validation for git-annex pushes branches.

They've ran into issues pushing big files because their git hook that checks commit messages triggered when they were pushing file using git annex.

***
* [new branch] git-annex -> origin/git-annex 
ok 
***
*remote: GitLab: Commit message does not follow the pattern 
'(([Tt]icket|[Rr]efs|[Ff]ix|[Ff]erme) #\d+|[Mm]erge).*'* 
To ***
! [remote rejected] git-annex -> synced/git-annex (pre-receive hook 
declined) 
! [remote rejected] master -> synced/master (pre-receive hook declined) 

This is also the case for the customer in https://gitlab.zendesk.com/agent/tickets/9339 where they have email validation that is failing.