documentation for context sample appears wrong

[John Haller]

In https://docs.openstack.org/rally/latest/plugins/implementation/context_plugin.html
there is a line in the sample code with this content:
from rally.plugins.openstack import osclients

I am only able to get this to work with this import line:
from rally_openstack import osclients

I assume this was a result of rally 1.0 separating the openstack plugin from rally itself,
but this part of the documentation didn't get the update.

It looks like this page also needs the update:
https://docs.openstack.org/rally/latest/plugins/implementation/scenario_plugin.html

[Andriy Kurilin (andreykurilin)]

let's track documentation issues here - https://bugs.launchpad.net/rally/+bug/1902703