small changes to section_launch-instance-nova
small changes to section_launch-instance-nova

changed keypair to key pair in title

Change-Id: I838a6a09d44c7c9db8dc4d5c1de76350d3c91ca1

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