Revert "grab default storage layout from the system instead of having it hardcoded for the switch."

This reverts commit 87d33abd3a22311225f9b313f9e818ffa1e52a55.
Revert "Storage: Allow user to choose internal storage"

This reverts commit 986bfb6c2ecb8c29c518be077ccdf195f93529c2.
Storage: Allow user to choose internal storage

Limited to devices that allow it (by presence of the ro.vold.switchablepair
property).

Ported from CM9's packages/apps/Settings

Previous Change-Id: I73439e167d0e2a08e2e922d5c0930cdeebe64940

Change-Id: I4514e8ebb2d41ef412adaee6967ee5dc52575971

Conflicts:
	src/com/android/settings/deviceinfo/Memory.java
Switch global storage environmental variables instead of actual mountpoints.
grab default storage layout from the system instead of having it hardcoded for the switch.