LU-10467 lustre: don't use l_wait_event() for poll loops.

LU-10467 lustre: don't use l_wait_event() for poll loops.

When polling without any usable wait queue, it is clearest
to have an explicit poll loop.
So don't use l_wait_event() in these two cases, but
use a while loop with ssleep(1);

Signed-off-by: Mr NeilBrown <neilb@suse.com>
Change-Id: Ic6a203085699fb9802d32871479c822ebe3c2510
Reviewed-on: https://review.whamcloud.com/35968
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>