Remove repetitive log statement

The log being removed seems is duplicated each time evalContext is
called, which seems like an unneeded debug log especially since the
iterationID information is outputted in various time in the debug logs.

hcl2template/types.packer_config.go

@@ -123,8 +123,6 @@ func (cfg *PackerConfig) EvalContext(ctx BlockContext, variables map[string]cty.
 
 	iterID, ok := cfg.HCPVars["iterationID"]
 	if ok {
-		log.Printf("iterationID set: %q", iterID.AsString())
-
 		ectx.Variables[packerAccessor] = cty.ObjectVal(map[string]cty.Value{
 			"version":     cty.StringVal(cfg.CorePackerVersionString),
 			"iterationID": iterID,