Change the log message for existing variable

Dumping the actual scope of existing variables that are preserved
in the merge is useful for debugging.  However, most of the scope
values are referenced by Id so the output is not very useful for
an end user.

source/OctopusTools/Importers/LibraryVariableSetImporter.cs

@@ -187,7 +187,7 @@ void MergeVariables(ICollection<VariableResource> variables, ICollection<Variabl
         {
             foreach (var existingVariable in existingVariables.Where(v => !VariableExists(v, variables)))
             {
-                Log.InfoFormat("Preserving existing variable '{0}' with scope '{1}'", existingVariable.Name, existingVariable.Scope);
+                Log.InfoFormat("Preserving existing variable '{0}'", existingVariable.Name);
 
                 // Need to give the existing variable a new unique Id before we can reuse it.
                 existingVariable.Id = Guid.NewGuid().ToString();