fixed minor issue in build file

build.go

@@ -279,6 +279,7 @@ func grunt(params ...string) {
 
 func setup() {
 	runPrint("go", "get", "-v", "github.com/tools/godep")
+	runPrint("go", "get", "-v", "github.com/blang/semver")
 	runPrint("go", "get", "-v", "github.com/mattn/go-sqlite3")
 	runPrint("go", "install", "-v", "github.com/mattn/go-sqlite3")
 }