dlm: use LSFL_FS to check for kernel lockspace

The existing external lockspace flag DLM_LSFL_FS is now also
saved as an internal flag LSFL_FS, so it can be checked from
other code locations which want to know if a lockspace is
used from the kernel or user space.

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