Allow statsd to write stats log events to perfd(running as shell) via pipes.

Bug: 120921905
Test: locally tested
Change-Id: I23fda0f83daff8765f7946814a61588dac00c85a

public/statsd.te

@@ -66,7 +66,7 @@ hal_client_domain(statsd, hal_thermal)
 # Allow 'adb shell cmd' to upload configs and download output.
 allow statsd adbd:fd use;
 allow statsd adbd:unix_stream_socket { getattr read write };
-allow statsd shell:fifo_file { getattr read };
+allow statsd shell:fifo_file { getattr read write };
 
 unix_socket_send(statsd, statsdw, statsd)