Using correct comment format in installVoltctl keyword

Change-Id: I9df4cb0b597636b1db7f06db11dbdf95f59774c8
diff --git a/vars/installVoltctl.groovy b/vars/installVoltctl.groovy
index d81c9ed..827d890 100644
--- a/vars/installVoltctl.groovy
+++ b/vars/installVoltctl.groovy
@@ -1,4 +1,4 @@
-# This keyword will install the voltctl based on the branch (e.g.: voltha-2.8 or master)
+// This keyword will install the voltctl based on the branch (e.g.: voltha-2.8 or master)
 def call(String branch) {
   sh returnStdout: false, script: """
     mkdir -p $WORKSPACE/bin