Fix T66390: Update missing when snaping strips.

Effect strips bound recalculation was mixed with overlap handling, which
caused, that effects wasn't handled.

In some cases there may be problem with order of strips in seqbase. We should
traverse hierarchy instead. This is design issue that applies to all
operators, and should be fixed separately.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D7880

source/blender/editors/space_sequencer/sequencer_edit.c

@@ -1403,7 +1403,11 @@ static int sequencer_snap_exec(bContext *C, wmOperator *op)
         BKE_sequence_base_shuffle(ed->seqbasep, seq, scene);
       }
     }
-    else if (seq->type & SEQ_TYPE_EFFECT) {
+  }
+
+  /* Recalculate bounds of effect strips. */
+  for (seq = ed->seqbasep->first; seq; seq = seq->next) {
+    if (seq->type & SEQ_TYPE_EFFECT) {
       if (seq->seq1 && (seq->seq1->flag & SELECT)) {
         BKE_sequence_calc(scene, seq);
       }