smbd: Pull mtime handling into open_file_ntcreate

smbd: Pull mtime handling into open_file_ntcreate

This is a performance improvement for heavily contended files, in
particular in a cluster. The separate call to get_file_infos makes us
pull the locking.tdb record twice per open. For a contended file this
can be a performance penalty, this gets the # of record accesses for
the open/close cycle down from 3 to 2.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Sat Nov 23 00:40:49 CET 2013 on sn-devel-104