fetch: use BPN instead
When checking for the non-existing file, BPN is actually the acutal recipe
name. And we should use BPN for the error message and it also fix the below
test when multilib is enabled.
$ oe-selftest -r bbtests.BitbakeTests.test_invalid_recipe_src_uri
Signed-off-by: Mingli Yu <mingli.yu@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>