releasetools: Don't extract BOOTABLE_IMAGES when signing target files

boot and recovery images need to be re-created during the signing
process to ensure that the proper keys are embedded in the images. Don't
extract the BOOTABLE_IMAGES path if it exists in the source target files
to avoid re-using the prebuilt versions.

Change-Id: Icdf61367efc2364f89c7ab1c61a81536431aea2e
Ticket: CYNGNOS-1994
1 file changed