Rename function deleteSSHKeysDeploymentMistake() to deleteUnusedDirectoriesCleanup()

I'm going to use this purge function for more than just removing a
signle direcotry.  I will purge another directory too, so renaming this
function to a more general name deleteUnusedDirectoriesCleanup().
Purge Apache/htdocs/ls/health_monitor/sandbox directory to cleanup