git-completion.bash: replace zsh notation that breaks bash 3.X
50c5885e (git-completion.bash: replace zsh notation that breaks bash
3.X, 2013-01-18) fixed a zsh-ism introduced earlier to append to an
array, which older versions of bash (3.0) did not grok. This was
again broken by
734b2f05 (completion: synchronize zsh wrapper,
2013-05-08).
Cherry-pick the fix again to let those with older bash use the
completion script.
Signed-off-by: Brandon Casey <drafnel@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>