[DS-2014] tweaked Vagrantfile to use the hosts' DNS resolver to speed up discovery of package repositories and make provisioning more dependable (less timeouts), pre-load the icedtea-7-plugin to help make update-java-alternatives more dependable, revamped how Java 7 is installed and set ast the default, to make Tomcat7 find it more reliably
fixed a typo, variable 'version' doesn't exist, but 'java_version' does
suggestion from Tim Donohue, removed hard coded version of the icedtea plugin
Merge pull request #21 from hardyoyo/DS-2014-Set-up-Java7-reliably

DS-2014 set up java7 reliably