Update deployment doc for /exports
Update deployment doc for /exports

Updated the deployment doc to remind users to create /exports if it doesn't exist.
virtuozzo/external-storage,aburluka/external-storage,clarkhale/external-storage,childsb/external-storage,virtuozzo/external-storage,dhirajh/external-storage,humblec/external-storage,aburluka/external-storage,kubernetes-incubator/external-storage,clarkhale/external-storage,clarkhale/external-storage,humblec/external-storage,dhirajh/external-storage,aburluka/external-storage,dhirajh/external-storage,kubernetes-incubator/external-storage,npramod/nfs-provisioner,kubernetes-incubator/external-storage,wongma7/nfs-provisioner-1,virtuozzo/external-storage,childsb/external-storage,aburluka/external-storage,dhirajh/external-storage,humblec/external-storage,childsb/external-storage