release: clean up after v0.11.8

CHANGELOG.md

+## 0.11.9 (Unreleased)
+
 ## 0.11.8 (August 15, 2018)
 
 NEW FEATURES:

version/version.go

@@ -11,12 +11,12 @@ import (
 )
 
 // The main version number that is being run at the moment.
-const Version = "0.11.8"
+const Version = "0.11.9"
 
 // A pre-release marker for the version. If this is "" (empty string)
 // then it means that it is a final release. Otherwise, this is a pre-release
 // such as "dev" (in development), "beta", "rc1", etc.
-var Prerelease = ""
+var Prerelease = "dev"
 
 // SemVer is an instance of version.Version. This has the secondary
 // benefit of verifying during tests and init time that our version is a