cellconfig: move memcpy outside loop

memcpy only needs to be done once prior to each entry into loop,
so move it outside the loop.

Change-Id: I68c09b240756f830b1a4dc9b8a338916f91cd7b2
Reviewed-on: http://gerrit.openafs.org/10872
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Tested-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>