intermittent CI failures - determine root cause and fix

typical log:

TASK [Set flag to indicate system is ostree] ***********************************
task path: /WORKDIR/git-revert_cmd43cwf684/tests/get_unused_disk.yml:10
Friday 26 January 2024  02:07:43 +0000 (0:00:00.118)       0:00:15.871 ******** 
ok: [sut] => {
    "ansible_facts": {
        "__snapshot_is_ostree": false
    },
    "changed": false
}

TASK [Ensure test packages] ****************************************************
task path: /WORKDIR/git-revert_cmd43cwf684/tests/get_unused_disk.yml:14
Friday 26 January 2024  02:07:43 +0000 (0:00:00.015)       0:00:15.886 ******** 
ok: [sut] => {
    "changed": false,
    "rc": 0,
    "results": [
        "util-linux-2.23.2-65.el7_9.1.x86_64 providing util-linux is already installed"
    ]
}

TASK [Find unused disks in the system] *****************************************
task path: /WORKDIR/git-revert_cmd43cwf684/tests/get_unused_disk.yml:28
Friday 26 January 2024  02:07:43 +0000 (0:00:00.385)       0:00:16.271 ******** 
ok: [sut] => {
    "changed": false,
    "disks": "Unable to find unused disk"
}

TASK [Set unused_disks if necessary] *******************************************
task path: /WORKDIR/git-revert_cmd43cwf684/tests/get_unused_disk.yml:36
Friday 26 January 2024  02:07:43 +0000 (0:00:00.197)       0:00:16.469 ******** 
skipping: [sut] => {
    "changed": false,
    "skip_reason": "Conditional result was False"
}

TASK [Exit playbook when there's not enough unused disks in the system] ********
task path: /WORKDIR/git-revert_cmd43cwf684/tests/get_unused_disk.yml:41
Friday 26 January 2024  02:07:43 +0000 (0:00:00.012)       0:00:16.481 ******** 
fatal: [sut]: FAILED! => {
    "changed": false
}

MSG:

Unable to find enough unused disks. Exiting playbook.

TASK [Clean up storage volumes] ************************************************
task path: /WORKDIR/git-revert_cmd43cwf684/tests/tests_check_no_lv_fail.yml:47
Friday 26 January 2024  02:07:43 +0000 (0:00:00.013)       0:00:16.495 ********
linux-system-roles / snapshot

intermittent CI failures - determine root cause and fix #18
