test-lib: Ignore --quiet under a TAP harness

Running the tests with --quiet under a TAP harness will always fail,
since a TAP harness always needs actual test output to go along with
the plan that's being emitted.

Change the test-lib.sh to ignore the --quiet option under
HARNESS_ACTIVE to work around this. Then users that have --quiet in
their GIT_TEST_OPTS can run tests under prove(1) without everything
breaking.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/test-lib.sh

@@ -127,7 +127,9 @@ do
 	-v|--v|--ve|--ver|--verb|--verbo|--verbos|--verbose)
 		verbose=t; shift ;;
 	-q|--q|--qu|--qui|--quie|--quiet)
-		quiet=t; shift ;;
+		# Ignore --quiet under a TAP::Harness. Saying how many tests
+		# passed without the ok/not ok details is always an error.
+		test -z "$HARNESS_ACTIVE" && quiet=t; shift ;;
 	--with-dashes)
 		with_dashes=t; shift ;;
 	--no-color)