[HAX] Allow per-target dtbTool

 * Revert this when fixed

Change-Id: I97ecb0448ae7bd5859454be290c5dde6248b2859
Merge branch 'cm-11.0' of github.com:CyanogenMod/android_build into cm-11.0
Merge branch 'cm-11.0' of https://github.com/temasek/android_build into cm-11.0