Cope with a (non-security) open race we've had for ever as NTCreateX isn't atomic...

Cope with a (non-security) open race we've had for ever as NTCreateX isn't atomic on POSIX.

On open without create, the file did exist, but some
other (local or NFS) process either renamed/unlinked
and re-created the file with different dev/ino after
we walked the path, but before we did the open. We
could retry the open but it's a rare enough case it's
easier to just fail the open to prevent creating any
problems in the open file db having the wrong dev/ino
key.

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Tue Jul 10 21:57:33 CEST 2012 on sn-devel-104