h265parse: Don't unref buffer that was unreffed just a few lines before already

Apply the commit 9b50a12

https://bugzilla.gnome.org/show_bug.cgi?id=754124
diff --git a/gst/videoparsers/gsth265parse.c b/gst/videoparsers/gsth265parse.c
index f76ce43..79e3fa5 100644
--- a/gst/videoparsers/gsth265parse.c
+++ b/gst/videoparsers/gsth265parse.c
@@ -872,7 +872,6 @@
     if (h265parse->split_packetized) {
       GST_ELEMENT_ERROR (h265parse, STREAM, FAILED, (NULL),
           ("invalid HEVC input data"));
-      gst_buffer_unref (buffer);
 
       return GST_FLOW_ERROR;
     } else {