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
Change-Id: Ia542a9df3e466a8d409955bab6a23a524ff3d07b
Bug: 11097631