vagrant: support other providers besides virtualbox

currently, we check for virtualbox to tell if we are deploying on a vagrant node. we should query if we are deploying to "local" nodes instead.

--- puppet/modules ‹develop M› » grep virtualbo -r         
site_config/manifests/default.pp:  if ( $::virtual == 'virtualbox' ) {
site_config/manifests/packages/base.pp:  if $::virtual == 'virtualbox' or $::services =~ /\bwebapp\b/ {
site_config/manifests/params.pp:  if $::virtual == 'virtualbox' {

(from redmine: created on 2013-10-15, closed on 2013-10-17, relates #4157 (closed))