Better warning when deleting a user

Git clone now gets the right branch from the getgo

Added Rake:Attack cp information to Upgrade Guide 6.3.0

Skip email confirmation with LDAP

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Before this commit gitlab-shell but me placed directly in home dir.
Ex:
  /home/git/gitlab-shell

After this change you can place gitlab-shell in custom location.
Ex:
  /Users/developer/gitlab/gitlab-shell
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Old behaviour gave you duplicate entries if your project is public
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fixed comments for running gitlab in a non-root path

Fix Markdown help page: escape file link syntax example to leave it unprocessed

Conflicts:
	config/application.rb
	config/gitlab.yml.example
	config/unicorn.rb.example

Read configuration variable file (/etc/default/gitlab) if it is present

fix typo: enthousiast -> enthusiast

Simplified the instructions by two steps.

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Warn the administrator better when deleting a user.
Fixes: https://github.com/gitlabhq/gitlabhq/issues/4295