Update installation.md

Add the -y option to the python apt-get install commands to be consistent with the rest of the Document.
Check if LDAP user was removed or blocked when use git over ssh
Merge branch 'feature/ssh_ldap_check' of /home/git/repositories/gitlab/gitlabhq
Expose votes in merge request api

Signed-off-by: Islam Amer <islam.amer@jollamobile.com>
Add user_id to system hook when new user created
Mention SystemHook user_id in sample. Extend tests
Merge branch 'mr_votes_api' of /home/git/repositories/gitlab/gitlabhq
Fix system hook page description
Merge branch 'feature/system_hook_user_id' of /home/git/repositories/gitlab/gitlabhq
Update merge requests from fork project to origin project

Fix error described in https://github.com/gitlabhq/gitlabhq/issues/5185
Merge pull request #5290 from zzet/patch-3

Update merge requests from fork project to origin project
Merge pull request #5278 from ZaaLabs/master

Small consistency addition for installation.md
avatar upload on profile page
Use proper titles for issues trackers
Merge pull request #5281 from Popl7/upload_avatar_to_gitlab

avatar upload on profile page
Improve Profile settings UI
Merge pull request #5291 from astratto/title_issue_trackers

Use proper titles for issues trackers
Remove test case that cause Mysql Deadlock
API: new feature - remove project[D
API: specs for remove project