Update logic for validates_merge_request for tree of MR

For case:

Merge request №1: branch "feature" to "release" and remove "feature" branch

Merge request №2: branch "release" to "master" and remove "release" branch

Merge request №1 - broken :(
Group owner or admin can remove other group owners
Remove project transfer page since we already have multiple owners for group
Namespaces.owner_id can be null
Group ownership completely based on users_groups relation now

Before we have only owner_id to determine group owner
With multiple owners per group we should get rid of owner_id in group.
So from now @group.owner will always be nil but
@group.owners return an actual array of users who can admin this group
Ignore owner_id for Group in tests
Mention group permissions on Help#permissions page
Mention permissions table on Group#members page
Merge branch 'refactor/group_owners' of /home/git/repositories/gitlab/gitlabhq
Remove issues search rspec since we test it with spinach too
Add sleep in tests to prevent random failing when next test starts before ajax requests for old one in progress
Fix issues search test
Dont test 1.9 with travis
Explain on dashboard that limit amount of projects displayed
Fixed grammatical mistake in init.d status output.

"its" not "it's".
Merge pull request #5192 from zshannon/patch-1

Fixed grammatical mistake in init.d status output.
Merge branch 'patch-2' of https://github.com/zzet/gitlabhq into zzet-patch-2

Conflicts:
	app/controllers/projects/merge_requests_controller.rb
Merge branch 'master' of github.com:gitlabhq/gitlabhq