fix typo in section_sdk_nova.xml
fix typo in section_sdk_nova.xml

when using nova_client.servers.list, miss parentheses

Change-Id: Ieede0bad2b6c7a9c6c0cb4983424222390196863

gongysh2004/openstack-manual,gongysh2004/openstack-manual,Akasurde/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,saeki-masaki/openstack-manuals,kairoaraujo/openstack-manuals,openstack/openstack-manuals,potsmaster/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,potsmaster/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,kairoaraujo/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,Akasurde/openstack-manuals,saeki-masaki/openstack-manuals