vutil use lockfile mutex macros for lockfile mutex

vutil use lockfile mutex macros for lockfile mutex

we have macroes; let's use them. makes later changes easier.

Change-Id: If128930f659c34592c27503a02d64b67d7f60a84
Reviewed-on: http://gerrit.openafs.org/2996
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Rod Widdowson <rdw@steadingsoftware.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>