WORKAROUND: mdadm hangs during reshape

WORKAROUND: mdadm hangs during reshape

During reshape when reshape is finished in md, progress_reshape() hangs
on select().
This is because 'sync_completed' is reset to zero before 'sync_action'
becomes 'idle', and we don't look for notification on 'sync_action'.

So if completed becomes zero after reshape_progress has made some
progress, then deduce that reshape has finished.

Signed-off-by: Adam Kwolek <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>