afs: Remove some unused bits

Remove three bits:

 (1) afs_server::no_epoch is neither set nor used.

 (2) afs_server::have_result is set and a wakeup is applied to it, but
     nothing looks at it or waits on it.

 (3) afs_vl_dump_edestaddrreq() prints afs_addr_list::probed, but nothing
     sets it for VL servers.

Signed-off-by: David Howells <dhowells@redhat.com>