zero: fix path of fstab for TWRP
zero: fix path of fstab for TWRP

Change-Id: I97932ed5b65968a677c1c45424eeab8981cbb86f

TeamNexus/android_device_samsung_zero-common,TeamNexus/android_device_samsung_zero-common,TeamNexus/android_device_samsung_zero-common,TeamNexus/android_device_samsung_zero-common,TeamNexus/android_device_samsung_zero-common