Added error codes to REST API docs
Added error codes to REST API docs

Change-Id: Ifc094fe887b18424d5d63565be6096feb6878fe3

openstack/sahara,henaras/sahara,rnirmal/savanna,bigfootproject/sahara,xme1226/sahara,crobby/sahara,keedio/sahara,henaras/sahara,zhujzhuo/Sahara,esikachev/sahara-backup,crobby/sahara,redhat-openstack/sahara,bigfootproject/sahara,zhujzhuo/Sahara,redhat-openstack/sahara,esikachev/sahara-backup,mapr/sahara,rnirmal/savanna,bigfootproject/sahara,ekasitk/sahara,xme1226/sahara,redhat-openstack/sahara,zhangjunli177/sahara,esikachev/scenario,ekasitk/sahara,citrix-openstack-build/sahara,zhangjunli177/sahara,matips/iosr-2015,esikachev/scenario,tellesnobrega/storm_plugin,mapr/sahara,tellesnobrega/storm_plugin,keedio/sahara,zhangjunli177/sahara,egafford/sahara,keedio/sahara,xme1226/sahara,matips/iosr-2015,esikachev/sahara-backup,citrix-openstack-build/sahara,zhujzhuo/Sahara,matips/iosr-2015,mapr/sahara,egafford/sahara,tellesnobrega/sahara,citrix-openstack-build/sahara,crobby/sahara,henaras/sahara,ekasitk/sahara,tellesnobrega/sahara,tellesnobrega/storm_plugin,esikachev/scenario,openstack/sahara