volser: Do not reset copyDate in ReClone

volser: Do not reset copyDate in ReClone

When we ReClone in the volserver, do not reset the clone's copyDate to
the current time. If we retain the copyDate between ReClone
operations, then we can know when the clone was first created (and
thus makes local RO clones more consistent with remote RO sites).

Change-Id: Ic76862c1a03ee3cafaf199f414fabc90e3b058d2
Reviewed-on: http://gerrit.openafs.org/3892
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>