package.bbclass: enable the use of package_qa_handle_error
This will allow the reporting of these errors as either WARNINGs (default)
or ERRORs if installed_vs_shipped is added to the ERROR_QA of the policy
file (such as a <distro_name>.conf file.
V2: found the code I had intended to send instead of that other junk,
was just not watching what I pushed on that one, sorry. (this is edit in
no in the actual commit message)
