Fix layout recreation check

Change I7d6b088a9235362e03cb6694392df71bbf5a323a added a relayout
for programmatic text direction changes, but this is breaking some
fixed layouts. Make sure layout params exist before trying to
act on them

Change-Id: Ibfe3daa71490d109c9a4bdc4c90cbf9517e53260
Framework changes for moving applications to external volume

* Add static functions for retrieving external apps volume information
* Determine external apps volume using the 'externalApps' attribute in
  storage_list.xml
* Allow moving applications to an external volume regardless if the
  internal storage is emulated or not
* Check if app moving is disabled

Thanks to Pierre-Hugues Husson for identifying an issue causing the
SD card state to be incorrect (ie. SD card appearing unmounted when a
USB drive is unplugged)

Change-Id: I5561c2cf3f558b729c89663852173a532994a47a