Merge branch 'jk/test-match-signal' into maint

The test framework learned a new helper test_match_signal to check an exit code from getting killed by an expected signal. * jk/test-match-signal: t/lib-git-daemon: use test_match_signal test_must_fail: use test_match_signal t0005: use test_match_signal as appropriate tests: factor portable signal check out of t0005