Put ANDROID_BUILD_PATHS before the system default PATH
Put ANDROID_BUILD_PATHS before the system default PATH

So tools like adb that are built from source won't be overridden by the
host system tools, when you run these tools without specifying the path.

Change-Id: I2f0a288b38fabf57c7a4aa3bae5e42d7b734398d

xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build