Bump go to 1.9.4 for build telegraf packages

Change-Id: I6dd3b922ed2c27e7c64aa6172b916c6f451cf687
diff --git a/build-debian-packages-telegraf.groovy b/build-debian-packages-telegraf.groovy
index 566c097..16d6259 100644
--- a/build-debian-packages-telegraf.groovy
+++ b/build-debian-packages-telegraf.groovy
@@ -47,8 +47,8 @@
                 }
                 stage("build package") {
                     img.inside{
-                        sh("""wget https://storage.googleapis.com/golang/go1.9.2.linux-amd64.tar.gz &&
-                            tar xf go1.9.2.linux-amd64.tar.gz &&
+                        sh("""wget https://storage.googleapis.com/golang/go1.9.4.linux-amd64.tar.gz &&
+                            tar xf go1.9.4.linux-amd64.tar.gz &&
                             export GOROOT=\$PWD/go &&
                             export PATH=\$PATH:\$GOROOT/bin &&
                             export GOPATH=\$PWD &&