Bugfixes and clarifications in Beaker docs
Bugfixes and clarifications in Beaker docs

The `bundle exec rake beaker` example was broken because `RS_SET`
is required.

The `RS_SET` isn't really meant to be user-visible, instead use
the pre-defined rake tasks.

Signed-off-by: Daniel Farrell <65eaad88897e615d9128b5e890b98414aac720cc@redhat.com>

umeshksingla/puppet-opendaylight,umeshksingla/puppet-opendaylight,srisankethu/puppet-opendaylight,srisankethu/puppet-opendaylight,semihalf-kardach-stanislaw/puppet-opendaylight,semihalf-kardach-stanislaw/puppet-opendaylight,trozet/puppet-opendaylight,trozet/puppet-opendaylight