silence git gc --auto --quiet output

When --quiet is requested, gc --auto should not display messages unless
there is an error.

Signed-off-by: Tobias Ulmer <tobiasu@tmux.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/gc.c

@@ -217,9 +217,7 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 		 */
 		if (!need_to_gc())
 			return 0;
-		if (quiet)
+		if (!quiet)
-			fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
-		else
 			fprintf(stderr,
 					_("Auto packing the repository for optimum performance. You may also\n"
 					"run \"git gc\" manually. See "

t/t5400-send-pack.sh

@@ -174,8 +174,7 @@ test_expect_success 'receive-pack runs auto-gc in remote repo' '
 	    cd parent &&
 	    echo "Even more text" >>file.txt &&
 	    git commit -a -m "Third commit" &&
-	    git send-pack ../child HEAD:refs/heads/test_auto_gc >output 2>&1 &&
+	    git send-pack ../child HEAD:refs/heads/test_auto_gc
-	    grep "Auto packing the repository for optimum performance." output
 	) &&
 	test ! -e child/.git/objects/tmp_test_object
 '