Fix wrong RST option markup
Fix wrong RST option markup

The error message:
  WARNING: Malformed :option: u'errors=remount', does not contain
  option marker - or -- or / or +
":option:" markup is for the commmand-line options.

Change-Id: I697cf1d3f66315528511121fd9017eecdb77980b

AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals