namei: Remove namei_SetNonZLC

This function is unused. Remove it.

Change-Id: Ie48d5370187c851afdd7cd359115d9e74d001aae
Reviewed-on: http://gerrit.openafs.org/10197
Reviewed-by: D Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>