Label and allow access to /data/system/ndebugsocket.

Otherwise it defaults to the label of /data/system and
cannot be distinguished from any other socket in that directory.
Also adds allow rule required for pre-existing wpa_socket transition
to function without unconfined_domain.

Change-Id: I57179aa18786bd56d247f397347e546cca978e41
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>