Revert "afs: shake harder in shake-loose-vcaches"

Revert "afs: shake harder in shake-loose-vcaches"

This reverts commit 5ba144bcf9e4df4c0ac960b2dd885649c040be25 which
does fix a real problem but unfortunately unmasks another one.

This is a 1.6 only change. A proper fix will hopefully be developed
on the master branch and then backported.

Change-Id: I81d4af8c07dbd983ea693f5e1de112830c2b6794
Reviewed-on: https://gerrit.openafs.org/12323
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>