Fix / refactor Oracle Linux 5 and 6 templates

Recently I've found some issues with the templates (Oracle Linux 5.9, 5.10, 6.4, 6.5) contributed by myself when using Veewee to Build Oracle Linux 6.5 and 5.10 Vagrant base boxes.

1. VirtualBox Additions installation could fail due to booting (reboot) into a newer version of the kernel (caused by `yum -y update` in `base.sh`). This will cause `vboxsf` validation failure. Issue fixed by moving the initial provisioning into Kickstart file, which is much more controllable and reliable when using DVD as install media.

2. Since RHEL 6, Kickstart syntaxes have changed. In the Kickstart file `ks.cfg`, `%package` MUST end with `%end`. EL 6 Kickstart installation still works without it BUT will certainly fail when using the same `ks.cfg` to install EL 7.

3. Removed duplicated `-auth --useshadow --enablemd5` from `ks.cfg`.

4. Some minor updates.