Free file handle for /firmware/image after use

Change-Id: Id59e25486b45dffc87a89a961970a6e8128a5237
Add writable data space for radio.

Storing carrier provisioning urls updates in /data/misc/radio.
bug:9623159

Change-Id: I8d62d4638229733dea0f11f1729c4d22ae2295d1