t4216: avoid unnecessary subshell in test_bloom_filters_not_used

Seems to trigger a bug in at least OpenBSD's 6.7 sh where it is
interpreted as a history lookup and therefore fails 125-126, 128,
130.

Remove the subshell and get a space between ! and grep, so tests
pass successfully.

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: carenas

t/t4216-log-bloom.sh

@@ -70,7 +70,7 @@ test_bloom_filters_used () {
 test_bloom_filters_not_used () {
 	log_args=$1
 	setup "$log_args" &&
-	!(grep -q "statistics:{\"filter_not_present\":" "$TRASH_DIRECTORY/trace.perf") &&
+	! grep -q "statistics:{\"filter_not_present\":" "$TRASH_DIRECTORY/trace.perf" &&
 	test_cmp log_wo_bloom log_w_bloom
 }