test-lib: turn on GIT_TEST_CHAIN_LINT by default

Now that the feature has had time to prove itself, and any
topics in flight have had a chance to clean up any broken
&&-chains, we can flip this feature on by default. This
makes one less thing submitters need to configure or check
before sending their patches.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/test-lib.sh

@@ -531,7 +531,7 @@ test_run_ () {
 	test_cleanup=:
 	expecting_failure=$2
 
-	if test "${GIT_TEST_CHAIN_LINT:-0}" != 0; then
+	if test "${GIT_TEST_CHAIN_LINT:-1}" != 0; then
 		# 117 is magic because it is unlikely to match the exit
 		# code of other programs
 		test_eval_ "(exit 117) && $1"