Fixed python3_sitelib for debbuild in OBS

Author: schaefi

package/python-kiwi_boxed_plugin-spec-template

@@ -29,7 +29,11 @@
 %endif
 
 %if %{undefined python3_sitelib}
+%if "%{_vendor}" == "debbuild"
 %global python3_sitelib %(%{__python3} -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())")
+%else
+%global python3_sitelib %(%{__python3} -c "import sysconfig; print(sysconfig.get_path('platlib'))")
+%endif
 %endif
 
 %if %{undefined python3_version}