viced: avoid bogus handle in rename

viced: avoid bogus handle in rename

because fileptr's handle can be reset during CopyOnWrite
we need to SetDirHandle after that call

FIXES 130215

Change-Id: I8578d30da42bdd9be2c552cdac4d2c526c22ee45
Reviewed-on: http://gerrit.openafs.org/5818
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>