Add refactor to Vanilla 1.2.1
Add refactor to Vanilla 1.2.1

We should refactor Vanilla plugin in such way to allow simple
applying event log feature

Change-Id: I76c64940ef86a86b7eab88c724f96fd49c674972
Closes-bug: #1411393

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