Issue #2315921 by jhedstrom: Fixed a fatal error that can occur during migrations.

field_collection.migrate.inc

@@ -89,15 +89,18 @@ class MigrateDestinationFieldCollection extends MigrateDestinationEntity {
    *   was saved or FALSE on failure.
    */
   public function import(stdClass $collection, stdClass $row) {
+    $updating = FALSE;
     if (isset($row->migrate_map_destid1)) {
       // We're updated an existing entity - start from the previous data.
       // entity_load() returns an array, so we get the field collection entity
       // with array_shift().
-      $entity = array_shift(entity_load('field_collection_item', array($row->migrate_map_destid1), array(), TRUE));
-      $entity_old = clone $entity;
-      $updating = TRUE;
+      if ($entity = array_shift(entity_load('field_collection_item', array($row->migrate_map_destid1), array(), TRUE))) {
+        $entity_old = clone $entity;
+        $updating = TRUE;
+      }
     }
-    else {
+
+    if (!$updating) {
       // Skip the collection if it has no host.
       if (empty($collection->host_entity_id)) {
         throw new MigrateException('Could not find host entity of the field collection to import.');