fs: dlm: LSFL_CB_DELAY only for kernel lockspaces

This patch only set/clear the LSFL_CB_DELAY bit when it's actually a
kernel lockspace signaled by if ls->ls_callback_wq is set or not set in
this case. User lockspaces will never evaluate this flag.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>