Merge pull request #4144 from edx/youngstrom/global_properties_fix

jenkins_common global properties template fix

playbooks/roles/jenkins_common/templates/config/properties_config.yml.j2

 ---
 {% for key_value in jenkins_common_system_properties %}
 - KEY: '{{ key_value.KEY }}'
-  VALUE: '{{ key_value.VALUE }}'
+  VALUE: "{{ key_value.VALUE }}"
 {% endfor %}