update CHANGELOG.md for 1.2.1

Author: rahushen

CHANGELOG.md

@@ -2,18 +2,7 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased]
-
-### New feature support
-*
-
-### Added
-*
-
-### Removed
-*
-
-## [1.2.1] - 2017-09-21
+## [1.2.1] - 2017-09-26
 
 ### Added
 - Update the cisco_node_utils vendored gem to version [1.7.0](https://github.com/cisco/cisco-network-node-utils/blob/develop/CHANGELOG.md#v170).