[CIFS] Do not negotiate new POSIX_PATH_OPERATIONS_CAP yet

Samba server now expects that clients which send the new
POSIX_PATH_OPERATIONS_CAP send all opens with this new
SMB - and expects that clients that could send the new
posix open/create but don't as indicating that they really
want Windows semantics on that handle (which allows Samba
to support clients which want to support both types of
behaviors on different handles on the same mount)

We will put this capability back in the SetFSInfo
negotiation with servers like Samba when the
new POSIXCreate (create/open/mkdir) code is finished.

Signed-off-by: Steve French <sfrench@us.ibm.com>