add ability for custom flags

roles/kubernetes/master/templates/manifests/kube-apiserver.manifest.j2

@@ -81,6 +81,9 @@ spec:
 {% if kube_api_anonymous_auth is defined and kube_version | version_compare('v1.5', '>=')  %}
     - --anonymous-auth={{ kube_api_anonymous_auth }}
 {% endif %}
+{% for flag in apiserver_custom_flags %}
+    - {{ flag }}
+{% endfor %}
     livenessProbe:
       httpGet:
         host: 127.0.0.1

roles/kubernetes/master/templates/manifests/kube-controller-manager.manifest.j2

@@ -46,6 +46,9 @@ spec:
     - --configure-cloud-routes=true
     - --cluster-cidr={{ kube_pods_subnet }}
 {% endif %}
+{% for flag in controller_mgr_custom_flags %}
+    - {{ flag }}
+{% endfor %}
     livenessProbe:
       httpGet:
         host: 127.0.0.1

roles/kubernetes/master/templates/manifests/kube-scheduler.manifest.j2

@@ -27,6 +27,9 @@ spec:
     - --leader-elect=true
     - --master={{ kube_apiserver_endpoint }}
     - --v={{ kube_log_level }}
+{% for flag in scheduler_custom_flags %}
+    - {{ flag }}
+{% endfor %}
     livenessProbe:
       httpGet:
         host: 127.0.0.1