add 1.2 release blog, update how to release guide
Project: http://git-wip-us.apache.org/repos/asf/kylin/repo
Commit: http://git-wip-us.apache.org/repos/asf/kylin/commit/20104d3d
Tree: http://git-wip-us.apache.org/repos/asf/kylin/tree/20104d3d
Diff: http://git-wip-us.apache.org/repos/asf/kylin/dif
Repository: kylin
Updated Branches:
refs/heads/1.x-staging ef4c524fc -> 20104d3d9
add 1.2 release blog, update how to release guide
Project: http://git-wip-us.apache.org/repos/asf/kylin/repo
Commit: http://git-wip-us.apache.org/repos/asf/kylin/commit/20104d3d
Tree: http://git-wip-us.apache.or