ci: Clear fact cache before every run

Since the `remount.yml` playbook now tries to avoid redundant remounts,
it needs up-to-date facts about mounted filesystems and their options.
If the cached facts are out of date, it may incorrectly skip remounting
a filesystem.  Besides, having up-to-date facts in the CI pipeline is
probably a good thing anyway.

vars/applyConfigPolicy.groovy

@@ -48,6 +48,7 @@ def stageKinit() {
         )]) {
             sh 'cp "${SUDO_PASS_FILE}" group_vars/pyrocufflink/sudo-pass'
         }
+        sh 'rm -rf .fact-cache'
     }
 }