flxdec: Don't unref() parent in the chain function

We don't own the reference here, it is owned by the caller and given to
us for the scope of this function. Leftover mistake from 0.10 porting.

https://bugzilla.gnome.org/show_bug.cgi?id=774897

gst/flx/gstflxdec.c

@@ -677,7 +677,6 @@ wrong_type:
   {
     GST_ELEMENT_ERROR (flxdec, STREAM, WRONG_TYPE, (NULL),
         ("not a flx file (type %x)", flxh->type));
-    gst_object_unref (flxdec);
     return GST_FLOW_ERROR;
   }
 }