netd: allow tcp connections.

DNS can use TCP connections, in addition to UDP connections.
Allow TCP connections.

Addresses the following denial:

[ 1831.586826] type=1400 audit(1384129166.563:173): avc:  denied  { create } for  pid=11406 comm="netd" scontext=u:r:netd:s0 tcontext=u:r:netd:s0 tclass=tcp_socket

Public Bug: https://code.google.com/p/android/issues/detail?id=62196
Bug: 11097631

(cherry picked from commit 36a5d109)

Change-Id: Id2e383e1c74a26ef7e56499a33bf2b06b869c12b