Remove clients-related data from the install guide

Remove ch_clients.xml, not included in the install guide.

Remove the installer specific exemples from
common/section_cli_openrc.xml.

Change-Id: Ia503f7f2115923d11d39aa5a4db35d17c3729ea9
Closes-Bug: #1350877
Merge "Remove clients-related data from the install guide"