We used Mercurial (hg) for source control and most of our Jenkins jobs are multi-branch jobs.  They all have skipDefaultCheckout set to false and have a build step that calls `deleteDir` and then `checkout scm` (because it doesn't appear as though default checkout can do a clean checkout.)

When our version control server is goes down and then comes back up (like a reboot), all the multibranch builds are triggered even though nothing in the code has changed.  Additionally, the lose all their build history