vol: correct old conditional for IH_CONDSYNC

Two places in the vol package performed IH_CONDSYNC(vp->linkHandle)
only if AFS_NT40_ENV.  This was correct when the namei implementation
was windows only; however, this ifdef was apparently overlooked
when namei was implemented for UNIX.

Change-Id: I0cbe2c5c0a65ece0485b8c2d5a5f92eeb53725fe
Reviewed-on: http://gerrit.openafs.org/8815
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>