Load the persistent properties after decrypting the /data partition

Fix for bug 3415286.  The persistent properties are normally read early
in the boot process after /data is mounted.  However, for an encrypted
system, at that point /data is a tmpfs ramdisk.  This change adds a new
command to init (load_persist_props) to read the persistent properties,
and adds an action to init.rc to load the persistent properties.  This
action is triggered by setting a property in vold, but that's in a
different CL.

Change-Id: I74b3057974ee6029c29d956b76fef5566700d471
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 046ab3d..ce000d6 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -304,6 +304,9 @@
 on property:vold.decrypt=trigger_reset_main
     class_reset main
 
+on property:vold.decrypt=trigger_load_persist_props
+    load_persist_props
+
 on property:vold.decrypt=trigger_post_fs_data
     trigger post-fs-data