Accept '==' operator in cubes dependencies '==' is the operator used in the python dependencies specifications. See PEP 440 http://legacy.python.org/dev/peps/pep-0440/#version-specifiers Using the same operator in cubes dependencies allow to make setuptools handle the cubes dependencies while keeping cubicweb happy about the dependencies. Closes #4375144

usr/lib/PY_VERSION/*-packages/cubicweb/etwist/