t0010-validate.sh: return on cgit errors

The earlier segfault in cgit passed by unnoticed by this test-script due to
the pipe between cgit and sed.

There might be a more elegant solution to this problem, but my shellscript-
foo is weak.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

tests/t0010-validate-html.sh

@@ -7,9 +7,12 @@ test_url()
 {
 	tidy_opt="-eq"
 	test -z "$NO_TIDY_WARNINGS" || tidy_opt+=" --show-warnings no"
-	cgit_url "$1" | sed -e "1,4d" >trash/tidy-$test_count
+	cgit_url "$1" >trash/tidy-$test_count || return
+	sed -ie "1,4d" trash/tidy-$test_count || return
 	tidy $tidy_opt trash/tidy-$test_count
 	rc=$?
+
+	# tidy returns with exitcode 1 on warnings, 2 on error
 	if test $rc = 2
 	then
 		false