Merge branch 'cw/completion'

More command line completion (in contrib/) for recent additions.

* cw/completion:
completion: recognize more long-options
completion: teach remote subcommands to complete options
completion: teach replace to complete options
completion: teach ls-remote to complete options
completion: improve bash completion for git-add
completion: add subcommand completion for rerere
completion: teach submodule subcommands to complete options

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