Merge "Fix prometheus-alertmanager cluster bug"

ansible/roles/prometheus/templates/prometheus-alertmanager.json.j2

 {
-    "command": "/opt/prometheus_alertmanager/alertmanager --config.file=/etc/prometheus/alertmanager.yml --web.listen-address={{ api_interface_address }}:{{ prometheus_alertmanager_port }} --web.external-url={{ internal_protocol }}://{{ kolla_internal_fqdn }}:{{ prometheus_alertmanager_port }} {% if groups["prometheus-alertmanager"] | length > 1 %} --mesh.listen-address={{ api_interface_address }}:{{ prometheus_alertmanager_cluster_port }} {% for host in groups["prometheus-alertmanager"] %} --mesh.peer={{ hostvars[host]['ansible_' + hostvars[host]['api_interface']]['ipv4']['address'] }}:{{ hostvars[host]['prometheus_alertmanager_cluster_port'] }}{% endfor %}{% endif %} --storage.path /var/lib/prometheus",
+    "command": "/opt/prometheus_alertmanager/alertmanager --config.file=/etc/prometheus/alertmanager.yml --web.listen-address={{ api_interface_address }}:{{ prometheus_alertmanager_port }} --web.external-url={{ internal_protocol }}://{{ kolla_internal_fqdn }}:{{ prometheus_alertmanager_port }} {% if groups["prometheus-alertmanager"] | length > 1 %} --cluster.listen-address={{ api_interface_address }}:{{ prometheus_alertmanager_cluster_port }} {% for host in groups["prometheus-alertmanager"] %} --cluster.peer={{ hostvars[host]['ansible_' + hostvars[host]['api_interface']]['ipv4']['address'] }}:{{ hostvars[host]['prometheus_alertmanager_cluster_port'] }}{% endfor %}{% endif %} --storage.path /var/lib/prometheus",
     "config_files": [
         {
             "source": "{{ container_config_directory }}/prometheus-alertmanager.yml",