tests: clean after SANITY tests
Some of our tests try to make sure Git behaves sensibly in a
read-only directory, by dropping 'w' permission bit before doing a
test and then restoring it after it is done. The latter is needed
for the test framework to clean after itself without leaving a
leftover directory that cannot be removed.
Ancient parts of tests however arrange the above with
chmod a-w . &&
... do the test ...
status=$?
chmod 775 .
(exit $status)
which obviously would not work if the test somehow dies before it
has the chance to do "chmod 775". Rewrite them by following a more
robust pattern recently written tests use, which is
test_when_finished "chmod 775 ." &&
chmod a-w . &&
... do the test ...
Signed-off-by: Junio C Hamano <gitster@pobox.com>