vold: Support for moving crypto metadata

 * We have a situation where we need to move the crypto metadata
   from a partition footer to a new place. Add support for this.

Change-Id: I5ccc312f7f062d8a8215530957da9c6283ed7ca5
vold: Allow ASEC containers on an external volume when internal is emulated

Thanks to Pierre-Hugues Husson for the idea in this patch! The initial
implementation called createBindMounts() on all mount points regardless
of whether or not it was the SD card.

Change-Id: Ic2c45d275179099065a10e1e664a08efea66acf1

Conflicts:
	Android.mk
	VolumeManager.cpp