Increase git clone depth from 10 to 20

The following error occured when cloning ceph-ansible.

cmdline: git reset --hard 54f7983be281f88714cbc75d393efa637e37ce17
stderr: 'fatal: Could not parse object '54f7983be281f88714cbc75d393efa637e37ce17'.'"]

There had been more than 10 commits to ceph-ansible since
the previous OSA sha bump so the role could not be cloned
with depth=10. Double the clone depth to make this less
likley to happen.

Also mark openstack-ansible-deploy-aio_distro_metal-centos-8
job as non-voting due to unresolved ssl issues with a new
version of amqp.

Change-Id: Ia9a15a431fee9997f74c9bed40156c63f480408e

scripts/get-ansible-role-requirements.yml

@@ -125,7 +125,7 @@
         - name: Clone git repos (parallel)
           git_requirements:
             default_path: "{{ role_path_default }}"
-            default_depth: 10
+            default_depth: 20
             default_version: "master"
             repo_info: "{{ clone_roles }}"
             retries: "{{ git_clone_retries }}"
@@ -139,7 +139,7 @@
             dest: "{{ item.path | default(role_path_default) }}/{{ item.name | default(item.src | basename) }}"
             version: "{{ item.version | default('master') }}"
             refspec: "{{ item.refspec | default(omit) }}"
-            depth: "{{ item.depth | default('10') }}"
+            depth: "{{ item.depth | default('20') }}"
             update: true
             force: true
           with_items: "{{ clone_roles }}"

zuul.d/jobs.yaml

@@ -371,6 +371,7 @@
     name: openstack-ansible-deploy-aio_distro_metal-centos-8
     parent: openstack-ansible-deploy-aio
     nodeset: centos-8
+    voting: false
 
 - job:
     name: openstack-ansible-deploy-aio_nspawn-centos-8