ota: Generate recovery-from-boot.p file

This may be wanted to update the recovery with system updates

Change-Id: Iacd41be7a8018cbc08b2606485d446756910f506
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0

Conflicts:
	tools/releasetools/ota_from_target_files
Remove now obsolete device-specific setting.

By default recovery updates are disabled - see http://review.cyanogenmod.org/#/c/64564/