Fix failures of ansible-lint (#8401)

This fixes the following types of failures:
- empty-string-compare
- literal-compare
- risky-file-permissions
- risky-shell-pipe
- var-spacing

In addition, this changes .gitlab-ci/lint.yml to block the same issue
by using the same method at Kubespray CI.

roles/network_plugin/ovn4nfv/tasks/main.yml

@@ -9,6 +9,7 @@
   template:
     src: "{{ item.file }}.j2"
     dest: "{{ kube_config_dir }}/{{ item.file }}"
+    mode: 0644
   with_items:
     - {name: ovn-daemonset, file: ovn-daemonset.yml}
     - {name: ovn4nfv-k8s-plugin, file: ovn4nfv-k8s-plugin.yml}