allow hooks to ignore their standard input stream

Since ec7dbd145 (receive-pack: allow hooks to ignore its
standard input stream) the pre-receive and post-receive
hooks ignore SIGPIPE. Do the same for the remaining hooks
pre-push and post-rewrite, which read from standard input.
The same arguments for ignoring SIGPIPE apply.

Include test by Jeff King which checks that SIGPIPE does not
cause pre-push hook failure. With the use of git update-ref
--stdin it is fast enough to be enabled by default.

Signed-off-by: Clemens Buchacher <clemens.buchacher@intel.com>
Signed-off-by: Jeff King <peff@peff.net>

t/t5571-pre-push-hook.sh

@@ -109,23 +109,20 @@ test_expect_success 'push to URL' '
 	diff expected actual
 '
 
-# Test that filling pipe buffers doesn't cause failure
-# Too slow to leave enabled for general use
-if false
-then
-	printf 'parent1\nrepo1\n' >expected
-	nr=1000
-	while test $nr -lt 2000
-	do
-		nr=$(( $nr + 1 ))
-		git branch b/$nr $COMMIT3
-		echo "refs/heads/b/$nr $COMMIT3 refs/heads/b/$nr $_z40" >>expected
-	done
+test_expect_success 'set up many-ref tests' '
+	{
+		nr=1000
+		while test $nr -lt 2000
+		do
+			nr=$(( $nr + 1 ))
+			echo "create refs/heads/b/$nr $COMMIT3"
+		done
+	} | git update-ref --stdin
+'
 
-	test_expect_success 'push many refs' '
-		git push parent1 "refs/heads/b/*:refs/heads/b/*" &&
-		diff expected actual
-	'
-fi
+test_expect_success 'sigpipe does not cause pre-push hook failure' '
+	echo "exit 0" | write_script "$HOOK" &&
+	git push parent1 "refs/heads/b/*:refs/heads/b/*"
+'
 
 test_done