Merge branch 'tp/completion'

* tp/completion:
Fixup: Add bare repository indicator for __git_ps1
Add bare repository indicator for __git_ps1
completion: More fixes to prevent unbound variable errors
completion: Better __git_ps1 support when not in working directory
completion: Use consistent if [...] convention, not "test"
completion: For consistency, change "git rev-parse" to __gitdir calls

diff --cc contrib/completion/git-completion.bash
Simple merge