Add a yum install command to install prereqs for the guest additions inside of the virtualbox.sh script in the CentOS 6.5 template. This is in case people don't include the yum.sh script in their build; this makes the virtualbox.sh script more standalone.
Add a yum install command to install prereqs for the guest additions inside of the virtualbox.sh script in the CentOS 7.0 template. This is in case people don't include the yum.sh script in their build; this makes the virtualbox.sh script more standalone.