volinfo: Use new form of cmd_AddParamWithOffset

volinfo: Use new form of cmd_AddParamWithOffset

cmd_AddParmWithOffset was recently modified to change the order of
its arguments to something clearer. Modify vol-info to use this new
argument order

Change-Id: Id94badfffb4c41cc13abd727e5674c18c58311fb
Reviewed-on: http://gerrit.openafs.org/4802
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>