Add-ons "bl_info" was supported for add-ons which weren't registered,
however the real modules weren't handled causing module_bl_info()
to return dummy values when an extensions add-ons module was passed in.
This caused the minimum Blender version check after enabling an add-on
to do nothing.
Now the "bl_info" from extension modules is ignored and the bl_info
is created on demand from the manifest.