Remove unused variable

volser has apparently never supported bcrypt from the intial IBM
import.  There's no need to keep around the code to fetch that key.

Change-Id: I6c903f0016ef8129da7e52b4f08b38c390b847e9
Reviewed-on: http://gerrit.openafs.org/9808
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>