Updated changelog with new OpenTSDB enhancement, grafana#1177

Author: torkelo

CHANGELOG.md

@@ -3,6 +3,7 @@
 **Data sources**
 - [Issue #1525](https://github.com/grafana/grafana/issues/1525). InfluxDB: Full support for InfluxDB 0.9 with new adapted query editor
 - [Issue #2191](https://github.com/grafana/grafana/issues/2191). KariosDB: Grafana now ships with a KariosDB data source plugin, thx @masaori335
+- [Issue #1177](https://github.com/grafana/grafana/issues/1177). OpenTSDB: Limit tags by metric, OpenTSDB config option tsd.core.meta.enable_realtime_ts must enabled for OpenTSDB lookup api
 
 **New dashboard features**
 - [Issue #1144](https://github.com/grafana/grafana/issues/1144). Templating: You can now select multiple template variables values at the same time.