modify FindIndex to compare uuids

modify FindIndex to compare uuids

If FindIndex is provided a server address and entry has a valid
uuid, obtain the uuid for 'server' and use that search for a
matching entry.

This modification is necessary in order to permit operations
against multi-homed servers in split horizon DNS configurations.

Change-Id: I8929c500eb4f71c8cf0aa8328bc3b3a0345368aa
Reviewed-on: http://gerrit.openafs.org/3468
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>