volserver: Restore -allow-dotted-principals

volserver: Restore -allow-dotted-principals

Commit cd3492d0 converted volserver command-line parsing to use
libcmd. However, it accidentally also changed the
-allow-dotted-principals option to -dotted. Change it back to
-allow-dotted-principals for consistency with previous versions, as
well as other server processes.

Note that currently there are no public releases of OpenAFS containing
cd3492d0, so no public release has contained the -dotted option.

Change-Id: Ied07f0eb867a13591656daae00bc9e85a2c7f6c8
Reviewed-on: http://gerrit.openafs.org/10423
Reviewed-by: Marc Dionne <marc.c.dionne@gmail.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>