[rql annotation] add test and fix for bug introduced by 5004:4cc020ee70e2. While it sounded good, it wasn't because stinfo['relations'] didn't include anymore stinfo['typerels']
"""pre 3.6 bw compat"""# pylint: disable-msg=W0614,W0401fromwarningsimportwarnwarn('moved to cubicweb.mixins',DeprecationWarning,stacklevel=2)fromcubicweb.mixinsimport*