oeqa/utils: targetbuild: don't use bb.fetch anymore

oeqa/utils: targetbuild: don't use bb.fetch anymore

When running tests outside of the build system we can't use
bb.fetch anymore. It was nice but tests and their modules
need to rely on the data storage only as that gets exported.
This module is used by the oeqa/runtime/build* tests.

(From OE-Core rev: 3caf8e244ea94f62a93f3b40e73e15ea78fc2880)

Signed-off-by: Stefan Stanacar <stefanx.stanacar@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>