Apply cast from cfc9b348 to the else clause

Clang on FreeBSD complains about format string mismatch as well.

Change-Id: I8bf17571807acdcac460efb94d0388b5cac4fa6c
Reviewed-on: http://gerrit.openafs.org/9855
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>