vagrant up fails

a recent commit has broken the "vagrant up" command.

in the preinstall script, a missing directory causes the final command to return a failure status (even though it didn't really fail).  this happens now because all the commands after this were recently commented out.  the final command must return success or vagrant thinks the script failed.

also i tidied the code by removing the commented out code; we can retrieve old code from git revision history if a revert is needed.