I see no reason to maintain both yocto-layer and bitbake-layers.
adding leo and bitbake-layers bug dependency.
check for test cases and migrate as needed
yocto-layer has been removed: http://git.yoctoproject.org/clean/cgit.cgi/poky/commit/?id=31684e868588121a4fcc6a966a509e8281ec9f9d