ExternalStorageProvider: String mismatch with system language

Text of phone storage does not change when locale changes.

Obtain the string each time by querying the database.

CRs-fixed: 739290

Change-Id: Ic6f5292f8eef9c9438e80fa876b8f276f21e26c8
UsbSettings: Add UMS mode support.

Add Usb Mass storage mode support for Android device;
Fix SD card can not be mounted to device when usb cable
is plugged in or unplugged fast and frequently.

Change-Id: Iff6de6b1b3e066f4a4ab610ae3fe10b22f5b0822