Don't show "Eject card" if the card is not accessible

SD card is not accessible without removing the battery on some devices.
Remove the "Eject" options on those devices

Depends on http://review.cyanogenmod.org/62708

Change-Id: Iddfa72314f7c96579ddd98e8fb312236348b7c2d
Show "Eject card" for usb storage

Readd the "Eject" options if the SD card is mounted via usb.

Change-Id: I802cf4d20eb3b45ce068f89c22352f79999d593e