Your eclass inherits base.eclass. For several reasons, we at the QA team would like to remove base, and so we ask that you remove the inherit. See bug 497022 for notes on transitioning your eclass away from the base inherit and checking for problems that could crop up.
@gnome, the fix for this looks pretty easy, simply drop base_src_install_docs in favor of einstalldocs (from eutils.eclass)
No longer there.