SELinux: Use custom ADB over network property

* Use a custom system property to trigger the real one, so we avoid
  running afoul of any SELinux CTS requirements.

Change-Id: If5e7a275f492631a673284408f1e430a12358380
diff --git a/prebuilt/common/etc/init.local.rc b/prebuilt/common/etc/init.local.rc
index 3868785..e29b015 100644
--- a/prebuilt/common/etc/init.local.rc
+++ b/prebuilt/common/etc/init.local.rc
@@ -139,6 +139,9 @@
     keycodes 114 115 116
 
 # adb over network
+on property:adb.network.port=*
+    setprop service.adb.tcp.port ${adb.network.port}
+
 on property:service.adb.tcp.port=5555
     stop adbd
     start adbd