Revert "allow init to auto-guess the correct fstab based on the ISD partition."

This reverts commit 95f21453ea9c6c2ccd27f1ad992f6a58d62ba017.
symlink fstab
patching init to get the 'right' fstab was a bad idea as vold has the path hardcoded. This patch changes init to symlink the correct fstab to the expected place