[DOC] Removed feature matrix for heat engine
[DOC] Removed feature matrix for heat engine

There is a feature parity between heat and direct engines. There is
no need in feature matrix.

Change-Id: Id12d9e8eace33f64783f0e5f4c755df3f9bf38e7

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