install jmespath with ansible in order to run the test in the travis environment

.travis.yml

@@ -3,6 +3,7 @@ python:
 - '2.7'
 install:
 - pip install ansible==2.4.0
+- pip install jmespath
 script:
 - ansible-playbook -i tests/.meta/inventory tests/.meta/main.yml
 - for test in tests/*/; do ansible-playbook -i $test/inventory $test/test.yml; done