bitbake: bitbake-layers: ensure we exit if BBLAYERS_LAYERINDEX_URL is not set
We were printing an error here, but not exiting.
(Bitbake rev: ddcaf8950a0b1cc74806e1ad7b49a1de0ea0d2b1)
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>