changelog update feature 1041

CHANGELOG.md

@@ -38,6 +38,7 @@ based on _prefix_ in addition to globs. This means that a filter like
 - [#1060](https://github.com/influxdata/telegraf/pull/1060): TTL metrics added to MongoDB input plugin
 - [#1056](https://github.com/influxdata/telegraf/pull/1056): Don't allow inputs to overwrite host tags.
 - [#1035](https://github.com/influxdata/telegraf/issues/1035): Add `user`, `exe`, `pidfile` tags to procstat plugin.
+- [#1041](https://github.com/influxdata/telegraf/issues/1041): Add `n_cpus` field to the system plugin.
 
 ### Bugfixes