Add debugging

vars/installVoltctl.groovy
--------------------------
Add ENTER/LEAVE debug printfs in the script.
Easier to verify null port failure occurred after voltctl install.

error: error parsing local port 'null':
strconv.ParseUint: parsing "null": invalid syntax

Change-Id: I764222d8cc2291de8a8c1c5543597ac2070e1d01
diff --git a/vars/installVoltctl.groovy b/vars/installVoltctl.groovy
index 24b8404..4cd5cc0 100644
--- a/vars/installVoltctl.groovy
+++ b/vars/installVoltctl.groovy
@@ -2,6 +2,9 @@
 
 def call(String branch) {
 
+    String iam = 'vars/installVoltha.groovy'
+    println("** ${iam}: ENTER")
+
     // This logic seems odd given we branch & tag repositories
     // for release so hilight non-frozen until we know for sure.
     def released=[
@@ -98,6 +101,8 @@
     # Should use diff or md5sum here
     /bin/ls -l \$(which voltha)
   """
+
+    println("** ${iam}: LEAVE")
 }
 
 // [EOF]