While adding meta-hob layer, we need to detect whether it already
exists in current layers.
(Bitbake rev: b195823d19bcb71bd5eef19acfe22b2dd670d90a)
Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>