[test] Fix test breakage uncovered by previous changeset Now that Binary.__eq__ doesn't always return true, this test started failing. CWAttribute.defaultval is zpickled, and the description_format attribute is a String, meaning unicode, so adjust the expected test result.

missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/share/pyshared/cubicweb/skeleton/debian/rules.tmpl)