now depends on kombu 2.2.3

requirements/default.txt

@@ -1,3 +1,3 @@
 billiard>=2.7.3.10
 python-dateutil>=1.5,<2.0
-kombu>=2.2.1,<3.0
+kombu>=2.2.3,<3.0

setup.cfg

@@ -18,5 +18,5 @@ requires = uuid
            importlib
            billiard>=2.7.3.10
            python-dateutil >= 1.5
-           kombu >= 2.2.1
+           kombu >= 2.2.3
            ordereddict