Change .htaccess to redirect from old api_ext dir to api-ref.html
Change .htaccess to redirect from old api_ext dir to api-ref.html

fix bug 1188073

Change-Id: Idfa869dd970f113062fc7d8c6306b4d53f2e30ad

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