Linux 3.6: revalidate dentry op API change

Linux 3.6: revalidate dentry op API change

The nameidata argument is dropped, replaced by an unsigned flags
value.  The configure test is very specific; kernels with the
older API with a signed int flags value should fall through.

Reviewed-on: http://gerrit.openafs.org/7986
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 7413cd09a53f89882a46fd100bf6c501348f2188)

Change-Id: Ie68d70dcf414d24e7e980c8a8f35b83550d2da7c
Reviewed-on: http://gerrit.openafs.org/8083
Reviewed-by: Ken Dreyer <ktdreyer@ktdreyer.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>