pt_util: gcc warning fix

it's claimed these are not initialized before use.
squelch compiler errors. has to be in parent as otherwise
we will zero them in our loop where we potentially want the
parent group id, which is not on "this" line as we add members.

Change-Id: I3014765ad1935cbe20421560329b5bdf465db8af
Reviewed-on: http://gerrit.openafs.org/9840
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>