Windows: Do not pass relative paths to redirector

RDR_SetInitParams provides two paths to the redirector, the AFSCache
file path and the path of the %TEMP% environment variable.  If either
of these paths are relative paths and not absolute (or full) paths,
the redirector and the service will interpret them differently.
Ensure that the full paths are delivered to the redirector.

Reviewed-on: http://gerrit.openafs.org/9074
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit e9af3e644205d7fff2a47e6eaa4a028e783d2df4)

Change-Id: Idd9efa0bbeb08eea72d032ad6ddfb3eef645ae6b
Reviewed-on: http://gerrit.openafs.org/9101
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>