Deployment Failed With Permission Denied when /tmp is mounted with noexec flag

[Zhu Shengli]

Description
===========
Deployment failed with permission denied error during executing TASK [tripleo-keystone-resources : Create admin and service projects].

```
[Errno 13] Permission denied: '/tmp/ansible-tripleo-admin/ansible-tmp-1600869521.9836748-14081-71570802572665/AnsiballZ_os_project.py'
```

Actually exec permission bit of the python script mentioned in the error message is well configured, but the `/tmp` is mounted with `noexec` flag on my Undercloud because of security requirement, so it's not executable.

```
$ mount | grep /tmp
tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noexec,relatime,seclabel)
```

Steps to reproduce
==================

1. mount /tmp with `noexec` flag
2. openstack deploy.

Expected result
===============
Deployed successfully.

Actual result
=============
Failed.

Environment
===========
OSP16

Logs & Configs
==============

```
2020-09-23 21:58:41,709 p=303 u=mistral | TASK [tripleo-keystone-resources : Create admin and service projects] **********
2020-09-23 21:58:41,710 p=303 u=mistral | Wednesday 23 September 2020 21:58:41 +0800 (0:00:02.169) 1:05:18.181 ***
2020-09-23 21:58:41,849 p=303 u=mistral | included: /usr/share/ansible/roles/tripleo-keystone-resources/tasks/projects.yml for undercloud
2020-09-23 21:58:41,930 p=303 u=mistral | TASK [tripleo-keystone-resources : Async creation of Keystone project] *********
2020-09-23 21:58:41,931 p=303 u=mistral | Wednesday 23 September 2020 21:58:41 +0800 (0:00:00.220) 1:05:18.402 ***
2020-09-23 21:58:42,925 p=303 u=mistral | changed: [undercloud] => (item=admin) => {"ansible_job_id": "764312968366.957080", "ansible_loop_var": "tripleo_keystone_resources_project", "changed": true, "finished": 0, "results_file": "/root/.ansible_async/764312968366.957080", "started": 1, "tripleo_keystone_resources_project": "admin"}
2020-09-23 21:58:43,640 p=303 u=mistral | changed: [undercloud] => (item=service) => {"ansible_job_id": "400271196630.957308", "ansible_loop_var": "tripleo_keystone_resources_project", "changed": true, "finished": 0, "results_file": "/root/.ansible_async/400271196630.957308", "started": 1, "tripleo_keystone_resources_project": "service"}
2020-09-23 21:58:43,734 p=303 u=mistral | TASK [tripleo-keystone-resources : Check Keystone project status] **************
2020-09-23 21:58:43,734 p=303 u=mistral | Wednesday 23 September 2020 21:58:43 +0800 (0:00:01.803) 1:05:20.206 ***
2020-09-23 21:58:44,158 p=303 u=mistral | failed: [undercloud] (item={'started': 1, 'finished': 0, 'ansible_job_id': '764312968366.957080', 'results_file': '/root/.ansible_async/764312968366.957080', 'changed': True, 'failed': False, 'tripleo_keystone_resources_project': 'admin', 'ansible_loop_var': 'tripleo_keystone_resources_project'}) => {"ansible_job_id": "764312968366.957080", "ansible_loop_var": "tripleo_keystone_resources_project_async_result_item", "attempts": 1, "changed": false, "cmd": "/tmp/ansible-tripleo-admin/ansible-tmp-1600869521.9836748-14081-71570802572665/AnsiballZ_os_project.py", "finished": 1, "msg": "[Errno 13] Permission denied: '/tmp/ansible-tripleo-admin/ansible-tmp-1600869521.9836748-14081-71570802572665/AnsiballZ_os_project.py'", "outdata": "", "stderr": "", "stderr_lines": [], "tripleo_keystone_resources_project_async_result_item": {"ansible_job_id": "764312968366.957080", "ansible_loop_var": "tripleo_keystone_resources_project", "changed": true, "failed": false, "finished": 0, "results_file": "/root/.ansible_async/764312968366.957080", "started": 1, "tripleo_keystone_resources_project": "admin"}}
2020-09-23 21:58:44,413 p=303 u=mistral | failed: [undercloud] (item={'started': 1, 'finished': 0, 'ansible_job_id': '400271196630.957308', 'results_file': '/root/.ansible_async/400271196630.957308', 'changed': True, 'failed': False, 'tripleo_keystone_resources_project': 'service', 'ansible_loop_var': 'tripleo_keystone_resources_project'}) => {"ansible_job_id": "400271196630.957308", "ansible_loop_var": "tripleo_keystone_resources_project_async_result_item", "attempts": 1, "changed": false, "cmd": "/tmp/ansible-tripleo-admin/ansible-tmp-1600869522.929629-14081-134095923524494/AnsiballZ_os_project.py", "finished": 1, "msg": "[Errno 13] Permission denied: '/tmp/ansible-tripleo-admin/ansible-tmp-1600869522.929629-14081-134095923524494/AnsiballZ_os_project.py'", "outdata": "", "stderr": "", "stderr_lines": [], "tripleo_keystone_resources_project_async_result_item": {"ansible_job_id": "400271196630.957308", "ansible_loop_var": "tripleo_keystone_resources_project", "changed": true, "failed": false, "finished": 0, "results_file": "/root/.ansible_async/400271196630.957308", "started": 1, "tripleo_keystone_resources_project": "service"}}
```

[Zhu Shengli (akarei)]

I found that the `ansible_remote_tmp` is set as `/tmp/ansible-${USER}` for fixing an issue.

https://review.opendev.org/#/c/577544

As far as I know the variable(in the `inventory.yaml`) takes the highest precedence for ansible configuration, so I guess there is no way I can override it? Is that possible to make `ansible_remote_tmp` configurable or add a condition for covering the `noexec` corner case?