Allow using "Parent: term name" on multiple columns

If you have a term importer with a source that can set multiple parents to a single term you may want to use multiple columns as "Parent: term name". But his will result in errors if you have rows that don't have all parent rows fill (some terms have only 1 parent, some have 2, some have 3) because feeds will try to insert the same key multiple times to the term_hierarchy table (term_id and parent ID as 0 multiple times).

On my case the solution is just to eliminate this lines from FeedsTermProcessor.inc

--- a/plugins/FeedsTermProcessor.inc
+++ b/plugins/FeedsTermProcessor.inc
@@ -134,12 +134,6 @@ class FeedsTermProcessor extends FeedsProcessor {
           if (!empty($parent_tid)) {
             $target_term->parent[] = $parent_tid;
           }
-          else {
-            $target_term->parent[] = 0;
-          }
-        }
-        else {
-          $target_term->parent[] = 0;
         }
         break;
       case 'parentguid':

Because if you are setting the parent for a term you almost always don't need to set any missing parents as 0.