CentOS 6.4 won't install with only 384MB of RAM -- this was fixed in the vmware section but not in the virtualbox section, so copy it.
Merge pull request #102 from juliandunn/centos-6-increase-memory

CentOS 6.4 won't install with only 384MB of RAM
setting selinux to permissive by default. testing of selinux cookbook is broken with disabled