Add /boot files as ramdisk_boot_file.

/boot/etc/build.prop is a file available at first_stage_init to
be moved into /second_stage_resources.

The file is only read by first_stage_init before SELinux is
initialized. No other domains are allowed to read it.

Test: build aosp_hawk
Test: boot and getprop
Bug: 170364317
Change-Id: I0f8e3acc3cbe6d0bae639d2372e1423acfc683c7
6 files changed