LVMv2: phase out the use of mmcblk0p14 as extra space.

-With the implementation of LVMv2, we don't need to use mmcblk0p14
(/vendor, /system/vendor) as extra space.
-mmcblk0p14 is now in the logical volume group "lvpool" along with
mmcblk0p13 and mmcblk0p16.