doc: Fix a few typos in vlserver man page

Fix a few errors in the vlserver manpage, a typo in a word and a
few missing delimiters that mess up the formatting slightly.

Change-Id: I1ec9887dfcbfd4f2a38c0a15fe7760d99682a194
Reviewed-on: http://gerrit.openafs.org/9804
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>