[Travis] Add another check

Author: noxiouz

.travis.yml

@@ -8,5 +8,5 @@ install:
   - "pip install -r requirements.txt"
   - "sudo cp ci/distributed-flock.json /etc/distributed-flock.json"
   - "sudo apt-get install zookeeper zookeeperd"
-script: python setup.py nosetests
+script: "test \"$(zk-flock | head -n1)\" == \"Invalid number of arguments\" && python setup.py nosetests"
 after_success: coveralls