fixes #3262 - actually create "cache" file to save the time of the last host facts push

Without this line calling this script with --push-facts will never create a "cache" file under yaml/foreman/ to remember the last time it pushed the host facts to foreman, which will result in all puppetmaster needlessly sending _all_ host facts _every_ time this script is run (with --push-facts parameter).


http://projects.theforeman.org/issues/3262