metrics: Add init script for metrics_daemon.

This init script creates the metrics data directory (/data/misc/metrics)
and starts the daemon.

BUG: 22953527

Change-Id: I21cd36f38a7a3550bc755cef5699e9a6ac3dfb94
diff --git a/metricsd/init.metrics_daemon.rc b/metricsd/init.metrics_daemon.rc
new file mode 100644
index 0000000..ad78ea5
--- /dev/null
+++ b/metricsd/init.metrics_daemon.rc
@@ -0,0 +1,8 @@
+on boot
+    mkdir /data/misc/metrics 0700 system system
+
+service metrics_daemon /system/bin/metrics_daemon --uploader -nodaemon
+    class late_start
+    user system
+    group system dbus inet
+    seclabel u:r:brillo:s0