Fix exec plugin panic with single binary

fixes #1330

CHANGELOG.md

@@ -1,3 +1,12 @@
+## v1.0 beta 2 [unreleased]
+
+### Features
+
+### Bugfixes
+
+- [#1330](https://github.com/influxdata/telegraf/issues/1330): Fix exec plugin panic when using single binary
+- [#1336](https://github.com/influxdata/telegraf/issues/1336): Fixed incorrect prometheus metrics source selection
+
 ## v1.0 beta 1 [2016-06-07]
 
 ### Release Notes
@@ -50,7 +59,6 @@ time before a new metric is included by the plugin.
 - [#1316](https://github.com/influxdata/telegraf/pull/1316): Removed leaked "database" tag on redis metrics. Thanks @PierreF!
 - [#1323](https://github.com/influxdata/telegraf/issues/1323): Processes plugin: fix potential error with /proc/net/stat directory.
 - [#1322](https://github.com/influxdata/telegraf/issues/1322): Fix rare RHEL 5.2 panic in gopsutil diskio gathering function.
-- [#1336](https://github.com/influxdata/telegraf/issues/1336): Fixed incorrect prometheus metrics source selection
 
 ## v0.13.1 [2016-05-24]