Add a basic sanity reboot test collecting AVCs

In order to minimize possible damage on composes we need to be sure that a
system can boot and it doesn't generate any AVC denial.

This test reboots a machine and collects AVC, USER_AVC and SELINUX_ERR audit
messages into avc.log file which is propagated as test artifact.

tests/tests-reboot.yml

@@ -0,0 +1,49 @@
+---
+- hosts: localhost
+  vars:
+  - artifacts: "{{ lookup('env', 'TEST_ARTIFACTS')|default('./artifacts', true) }}"
+  tags:
+  - classic
+  tasks:
+  # switch SELinux to permissive mode
+  - name: Get default kernel
+    command: "grubby --default-kernel"
+    register: default_kernel
+  - debug: msg="{{ default_kernel.stdout }}"
+  - name: Set permissive mode
+    command: "grubby --args=enforcing=0 --update-kernel {{ default_kernel.stdout }}"
+
+  - name: reboot
+    block:
+      - name: restart host
+        shell: sleep 2 && shutdown -r now "Ansible updates triggered"
+        async: 1
+        poll: 0
+        ignore_errors: true
+
+      - name: wait for host to come back
+        wait_for_connection:
+          delay: 10
+          timeout: 300
+
+      - name: Re-create /tmp/artifacts
+        command: mkdir /tmp/artifacts
+
+      - name: Gather SELinux denials since boot
+        shell: |
+            result=pass
+            dmesg | grep -i -e type=1300 -e type=1400 > /tmp/avc.log && result=fail
+            ausearch -m avc -m selinux_err -m user_avc -ts boot >> /tmp/avc.log 2> /tmp/avc.err.log
+            grep -q '<no matches>' /tmp/avc.err.log || result=fail
+            echo -e "results:\n- test: reboot and collect AVC\n  result: $result\n" > /tmp/results.yml
+
+    always:
+      - name: Pull out the artifacts
+        fetch:
+          dest: "{{ artifacts }}/"
+          src: "{{ item }}"
+          flat: yes
+        with_items:
+          - /tmp/avc.log
+          - /tmp/avc.err.log
+          - /tmp/results.yml