wt-status: don't flush before running "submodule status"

This is a holdover from the original implementation in
ac8d5af (builtin-status: submodule summary support,
2008-04-12), which just had the sub-process output to our
descriptor; we had to make sure we had flushed any data that
we produced before it started writing.

Since 3ba7407 (submodule summary: ignore --for-status
option, 2013-09-06), however, we pipe the sub-process output
back to ourselves. So there's no longer any need to flush
(it does not hurt, but it may leave readers wondering why we
do it).

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

wt-status.c

@@ -745,7 +745,6 @@ static void wt_status_print_submodule_summary(struct wt_status *s, int uncommitt
 
 	sm_summary.git_cmd = 1;
 	sm_summary.no_stdin = 1;
-	fflush(s->fp);
 	sm_summary.out = -1;
 
 	run_command(&sm_summary);