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.

---
 t/test-lib.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 4ea99a2..39da9c2 100644
@@ -529,7 +529,7 @@ 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"

2.4.0.rc2.498.g02440db