[pkg] Depends on elasticsearch-dsl <5.0.0

Because version 5.0.0 depends on elasticsearch 5.0.0 and we
apparently do not want this as per parent changeset.

__pkginfo__.py

@@ -16,7 +16,7 @@
 __depends__ = {'cubicweb': '>= 3.22.2', 'six': '>= 1.4.0',
                'cwtags': None,
                'elasticsearch': '>=2.0.0,<3.0.0',
-               'elasticsearch-dsl': None,
+               'elasticsearch-dsl': '<5.0.0',
                'bs4': None,
 }
 __recommends__ = {}