remove unneeded sysctl changes in sysvinit-redhat init script

Docker-DCO-1.1-Signed-off-by: Adam Miller <admiller@redhat.com> (github: maxamillion)

We don't need these sysctl params.
The ipv4 one is no longer needed as per https://github.com/dotcloud/docker/pull/3801
The ipv6 one isn't necessary since there's no ipv6 support for docker.