viced: Check for HOSTDELETED in stillborn check

viced: Check for HOSTDELETED in stillborn check

h_FindClient_r checks the connection rock for a client object twice.
First it sees if we already have a client object, and if we don't, we
effectively create one (or find a suitable one). Then we check again,
to see if someone else set the rock while we were creating a client
structure.

Currently, the first check checks if client->host->hostFlags has
HOSTDELETED set, but the second check does not. So, if the host
associated with the client has been deleted by someone else, currently
we will unnecessarily log a "stillborn client" message, and we will
continue to use the deleted host. If the host continues to be held by
someone, we will run into the same situation repeatedly on future
requests until all of the host references go away.

To fix this, also ignore HOSTDELETED clients when performing the
stillborn race check.

Change-Id: Id72e83cb55b99a686d4179905116592e80eb9ac7
Reviewed-on: http://gerrit.openafs.org/5614
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>