Fix readme typo
Fix readme typo

Change-Id: I6f6dccba68708508b023d8306c60110d1240bd75

openstack/puppet-ironic,toby82/puppet-ironic,JioCloud/puppet-ironic,openstack/puppet-ironic,trown/puppet-ironic,rdo-puppet-modules/puppet-ironic,fuel-infra/puppet-ironic,trown/puppet-ironic,varunarya10/puppet-ironic,trown/puppet-ironic,rdo-puppet-modules/puppet-ironic,toby82/puppet-ironic,fuel-infra/puppet-ironic,openstack/puppet-ironic,fuel-infra/puppet-ironic