camerabin2: Set tagsetters to merge replace mode

The default for tagsetters is to use merge keep mode, so tags
would never be replaced and all captures would have the same tags.

This commit watches all elements added into encodebin and sets
all tagsetters to merge replace mode

gst/camerabin2/gstcamerabin2.c

@@ -828,6 +828,12 @@ encodebin_element_added (GstElement * encodebin, GstElement * new_element,
       g_object_set (new_element, "skip-to-first", TRUE, NULL);
     }
   }
+
+  if (gst_element_implements_interface (new_element, GST_TYPE_TAG_SETTER)) {
+    GstTagSetter *tagsetter = GST_TAG_SETTER (new_element);
+
+    gst_tag_setter_set_tag_merge_mode (tagsetter, GST_TAG_MERGE_REPLACE);
+  }
 }
 
 #define VIDEO_PAD 1