Store the value from TARGET_OTA_ASSERT_DEVICE to a file

This is needed so it can be read in when re-signing a package to
allow for the proper device asserts.

Change-Id: I8f3bb491bbbaa4d2b827a45ef83f12c6c83e6712

Conflicts:
	core/Makefile
GCC Freedom Script 4.8 & Some Optimizations.

--Thanks GNOME.
 Change to -O3 and add more flags