vfs: restore stat fields in vfs_stat_fsp()

vfs: restore stat fields in vfs_stat_fsp()

This ensures we preserve btime, itime and File-ID.

As the Durable Handles code calls vfs_stat_fsp() in the DH disconnect function,
previously the btime was lost and NOT stored in the cookie. With this change the
cookie will store the correct btime (and iflags), which requires us to call
dos_mode() in the reconnect function to ensure we pass
vfs_default_durable_reconnect_check_stat().

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14121

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Tue Sep 10 20:22:21 UTC 2019 on sn-devel-184

(cherry picked from commit 95655fe683d499d93f3844ed72ad332ef64adb96)

Autobuild-User(v4-11-test): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(v4-11-test): Tue Sep 10 22:29:08 UTC 2019 on sn-devel-184