Revert "Merge pull request #422 from svanharmelen/f-shaving-off-some-cpu-cycles"

This reverts commit 428cce2478, reversing
changes made to 517c5b2ea8.

helper/schema/resource_data.go

@@ -349,10 +349,12 @@ func (d *ResourceData) getSet(
 	var indexMap map[int]int
 	if len(parts) > 0 {
 		indexMap = make(map[int]int)
+	}
 
-		// Build the set from all the items using the given hash code
-		for i, v := range list {
-			code := s.add(v)
+	// Build the set from all the items using the given hash code
+	for i, v := range list {
+		code := s.add(v)
+		if indexMap != nil {
 			indexMap[code] = i
 		}
 	}