Move lmkd into it's own domain.

lmkd low memory killer daemon

The kernel low memory killer logic has been moved to a new daemon
called lmkd.  ActivityManager communicates with this daemon over a
named socket.

This is just a placeholder policy, starting off in unconfined_domain.

Change-Id: Ia3f9a18432c2ae37d4f5526850e11432fd633e10
diff --git a/system_server.te b/system_server.te
index 25ce2a4..f603ea3 100644
--- a/system_server.te
+++ b/system_server.te
@@ -73,6 +73,7 @@
 unix_socket_connect(system_server, property, init)
 unix_socket_connect(system_server, qemud, qemud)
 unix_socket_connect(system_server, installd, installd)
+unix_socket_connect(system_server, lmkd, lmkd)
 unix_socket_connect(system_server, netd, netd)
 unix_socket_connect(system_server, vold, vold)
 unix_socket_connect(system_server, zygote, zygote)