completion: support 'git config --local'
completion: support 'git config --local'

This needs to be done in two places: __git_config_get_set_variables to
allow clever completion of "git config --local --get foo<tab>", and
_git_config to allow "git config --loc<tab>" to complete to --local.

While we're there, change the order of options in the code to match
git-config.txt.

Signed-off-by: Matthieu Moy <d4d2cc2a6ec7b2aa587d4887cc5ed200f9b685a1@imag.fr>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git