fix(separate): dont attempt to load associations if parent results are empty, fixes #4217

lib/model.js

@@ -1342,6 +1342,8 @@ Model.$findSeperate = function(results, options) {
 
   var original = results;
   if (options.plain) results = [results];
+  
+  if (!results.length) return original;
 
   return Promise.map(options.include, function (include) {
     if (!include.separate) {