completion: improve existence check for pseudo-refs

Improve the existence check along the following lines:

  - Stop stripping the "ref :" prefix and compare to the expected value
    directly. This allows us to drop a now-unused variable that was
    previously leaking into the user's shell.

  - Mark the "head" variable as local so that we don't leak its value
    into the user's shell.

  - Stop manually handling the `-C $__git_repo_path` option, which the
    `__git ()` wrapper aleady does for us.

  - In simlar spirit, stop redirecting stderr, which is also handled by
    the wrapper already.

Suggested-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

0 files changed, 0 insertions, 0 deletions