Revert "build: Add support for PRODUCT_COPY_FILES_OVERRIDES"

This reverts commit 7f90437176b02af5f59ac4f55345924da80f664f.
Allow override of device asserts, including multi-device support.

Set in board file with TARGET_OTA_ASSERT_DEVICE.
(cherry-picked from commit 0f452f21fc9323b9d1fe746161761cf40aaa5030)

Change-Id: I3d06bdc0e3e26bde0c0e646accd050364f9713b9

Conflicts:

	tools/releasetools/edify_generator.py
	tools/releasetools/ota_from_target_files

Change-Id: I3d06bdc0e3e26bde0c0e646accd050364f9713b9

Conflicts:
	tools/releasetools/ota_from_target_files