salvager: incorrect comment

The comment for the code handling the -showsuid option was incorrect.

Change-Id: I0a63211cf5dd8a3b2636d4e4a2cc45a55c3bf62a
Reviewed-on: http://gerrit.openafs.org/9109
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>