Whitelist new CHANGE_OVERLAY_PACKAGES permission

The Shell application needs access to change which overlays are
enabled in OverlayManagerService.

Test: Manual: invoke adb exec-out cmd overlay enable some.package.name
when shell is not root (adb unroot on eng builds).
Change-Id: I1849f68e244cfc9b1e13eb0e673dde7be03cba6d
diff --git a/data/etc/privapp-permissions-platform.xml b/data/etc/privapp-permissions-platform.xml
index 5226fe5..bf3e793 100644
--- a/data/etc/privapp-permissions-platform.xml
+++ b/data/etc/privapp-permissions-platform.xml
@@ -253,6 +253,7 @@
         <permission name="android.permission.BIND_APPWIDGET"/>
         <permission name="android.permission.CHANGE_COMPONENT_ENABLED_STATE"/>
         <permission name="android.permission.CHANGE_CONFIGURATION"/>
+        <permission name="android.permission.CHANGE_OVERLAY_PACKAGES"/>
         <permission name="android.permission.CONNECTIVITY_INTERNAL"/>
         <permission name="android.permission.DELETE_CACHE_FILES"/>
         <permission name="android.permission.DELETE_PACKAGES"/>