gmarik/vundle — pull request #185 by snufrick (2012-06-20 07:00:30+00:00)
Title: Vundle can manage Vundle, when it cloned as git submodule

When vundle installed as git submodule, git create file '.git' instead of
directory '.git' .

When I do :BundleInstall 'autoload/vundle/installer.vim' think there is no '.git' directory in my 'bundle/vundle'
and try to clone vundle repo. It cause 'directory exists error'

Now we check for '.git' file exists and we think if this file readable, this is git repo.