This patch changes every occurrence of "! git" -- with the meaning
that a git call has to gracefully fail -- into "test_must_fail git".
This is useful to
- make sure the test does not fail because of a signal,
e.g. SIGSEGV, and
- advertise the use of "test_must_fail" for new tests.
Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>