Allow bluetooth users ioctl access to bluetooth unix stream socket.

Resolves denials such as:
avc:  denied  { ioctl } for  pid=6390 comm="m.wimmcompanion" path="socket:[472596]" dev="sockfs" ino=472596 scontext=u:r:untrusted_app:s0 tcontext=u:r:bluetooth:s0 tclass=unix_stream_socket

Change-Id: Idd4fa219fe8674c6e1c40211b3c105d6276cfc5a
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>