run-command: add braces for "if" block in wait_or_whine()

Add braces to an "if" block in the wait_or_whine() function. This
isn't needed now, but will make a subsequent commit easier to read.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

run-command.c

@@ -551,8 +551,9 @@ static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
 
 	while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 		;	/* nothing */
-	if (in_signal)
+	if (in_signal) {
 		return 0;
+	}
 
 	if (waiting < 0) {
 		failed_errno = errno;