Copy preopted files from B partition.

This translates from the preopted files in the system_other partition
into the main dalvik-cache. This also has init scripts to allow this
to run.

We first copy to a temporary file before renaming them in order to
make the copy atomic.

Bug: 29278988
Change-Id: I8bf1b2d021998949fd9996a923be7db9691e6a1e
5 files changed