Allow netd to write to statsd

config sepolicy to allow netd to write to statsd.

Test: run runtests.sh, make sure no missing test and get all pass
      run /out/host/linux-x86/bin/statsd_testdrive 82
      Got following metric data dump:pass for local test
Bug: 119862317

Change-Id: Ieff5ca55de46715d54ef57c4a6d144fd7d03e4b7

private/netd.te

@@ -13,3 +13,6 @@ domain_auto_trans(netd, clatd_exec, clatd)
 allow netd bpfloader:bpf { prog_run map_read map_write };
 
 get_prop(netd, bpf_progs_loaded_prop)
+
+# Allow netd to write to statsd.
+unix_socket_send(netd, statsdw, statsd)