locking: move share_mode_flags_[gs]et to share_mode_lock.c

locking: move share_mode_flags_[gs]et to share_mode_lock.c

These routines parse and marshall the uint16 summary flag in
share_mode_data. open_file_ntcreate() and open_directory() are the
only real users of this. The user in oplock.c is just the lazy reset
of the "read lease exists somewhere" after asynchronously breaking
read oplocks after a write request.

This moves handling the flags into locking/ to consolidate data
structure handling of "share_mode_data" there.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>