s3: smbd: Inside call_trans2setfilepathinfo(), for the TRANSACT2_SETPATHINFO case...

s3: smbd: Inside call_trans2setfilepathinfo(), for the TRANSACT2_SETPATHINFO case, ensure we have a VALID_STAT return from filename_convert().

Remember, filename_convert() can return NT_STATUS_OK
with !VALID_STAT() if the last component doesn't exist,
as this may be an object create.

For call_trans2setfilepathinfo(), there are only 4 info levels
for the TRANSACT2_SETPATHINFO (pathname) case that don't require
an existing filesystem object (i.e. a VALID_STAT()) in the return
from filename_convert() as they can create an object in the
filesystem.

If we don't get a VALID_STAT() and the info level isn't one of
those 4, error out.

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Noel Power <npower@samba.org>