Adding yamllinter to ci steps (#1556)

* Adding yaml linter to ci check

* Minor linting fixes from yamllint

* Changing CI to install python pkgs from requirements.txt

- adding in a secondary requirements.txt for tests
- moving yamllint to tests requirements

roles/kubernetes-apps/network_plugin/canal/tasks/main.yml

@@ -1,3 +1,4 @@
+---
 - name: Create canal ConfigMap
   run_once: true
   kube:
@@ -7,7 +8,7 @@
     resource: "configmap"
     namespace: "{{system_namespace}}"
 
-#FIXME: remove if kubernetes/features#124 is implemented
+# FIXME: remove if kubernetes/features#124 is implemented
 - name: Purge old flannel and canal-node
   run_once: true
   kube:
@@ -29,4 +30,3 @@
     namespace: "{{system_namespace}}"
     state: "{{ item | ternary('latest','present') }}"
   with_items: "{{ canal_node_manifest.changed }}"
-