product_config: Set CM_BUILD priority above TARGET_BUILD_APPS

Even if we are doing TARGET_BUILD_APPS, we may want to use a cm
target for building.

Change-Id: Ic8053bc679fa8b726be90e611aeaacdf1850cabc
(cherry picked from commit 20c8824db43edca252862c312ed7c1197f48919f)
build: don't clear recovery ramdisk

Clearing recovery ramdisk removes all files place there by the
device tree and all busybox symlinks placed there by recovery

Change-Id: I19e6164856a01a83a6e2c50ef96742edcb9f570f
(cherry picked from commit efd027c838968b2840dbe863360b1b9e1bb3efab)