Bug 1015113 - Disable including version.inc when building bootloader r=mwu

This file defines the vendor-specific bootloader version. This does not
makes a lot of sense for B2G itself, so we just disable including this
file. This will make the android.bootloader kernel command line argument
not being passed when booting the system.
Merge pull request #2 from lissyx/bug1015113-jb

Bug 1015113 - Disable including version.inc when building bootloader r=mwu