Update TW storage paths and remove unneeded flags

While these TW_INTERNAL_STORAGE_* definitions are mostly obsolete, there
still seems to be some crypto code that looks for them. Go ahead and
define them.

The flags removed from recovery.fstab are already generated by
partition.cpp, based on the mount point.

Change-Id: I7f165aac03c57a291c9be892da8f33bd6d326cc8