Added Doc conventions to glossary.
Added Doc conventions to glossary.

Change-Id: Icf2dcc52948e9d64568a0803a8a085f07abee4c6
Partial-Bug: #1121866

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