Revert " Set sdcard as non-removable (workaround for mediaprovider bug) "

See references for more info

Reference:

https://github.com/androidarmv6/android_frameworks_base/commit/3d459f082ab274117b021c9061490f77238976e9
Reference:

https://github.com/CyanogenMod/android_system_vold/commit/84aa7ed0171f5f64ba58d2d785a39004a7ba2886
Reference: http://review.cyanogenmod.org/#/c/66055/
Reference: http://review.cyanogenmod.org/#/c/66057/