Windows: cm_DumpServers "down" is string not enum

When dumping the state of the servers, "down" is a string not an
enum value.

Change-Id: I603755cf0db28515d01bc03253a4d3e6528b13aa
Reviewed-on: http://gerrit.openafs.org/9946
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>