MDL-47697 mod_data: Fix group id change when editing.

When a teacher edits an entry in the database module
it would change the group ID to the one that the teacher
currently had selected.

Thanks to Steve Bond for providing a patch.

mod/data/edit.php

@@ -168,7 +168,6 @@ if ($datarecord = data_submitted() and confirm_sesskey()) {
             $record->approved = 0;
         }
 
-        $record->groupid = $currentgroup;
         $record->timemodified = time();
         $DB->update_record('data_records', $record);