signal: remove jffs2_garbage_collect_thread()->allow_signal(SIGCONT)

jffs2_garbage_collect_thread() does allow_signal(SIGCONT) for no reason,
SIGCONT will wake a stopped task up even if it is ignored.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/jffs2/background.c

@@ -80,7 +80,6 @@ static int jffs2_garbage_collect_thread(void *_c)
 	siginitset(&hupmask, sigmask(SIGHUP));
 	allow_signal(SIGKILL);
 	allow_signal(SIGSTOP);
-	allow_signal(SIGCONT);
 	allow_signal(SIGHUP);
 
 	c->gc_task = current;