autoconnect fails with tsdemux and h264parse, it didn't try other decoders

Submitted by Jan Alexander Steffens @heftig

Link to original bug (#770535)

Description

URL:
https://vodcdn.mobcrush.com/u/video/57a5c1a051f31fbb6d62cd53/recording.mp4.m3u8

Attempting to play this stream fails with a not-negotiated error.

0:00:00.745837289 18551 0x1972ad0 WARN basetransform gstbasetransform.c:1414:gst_base_transform_setcaps:<capsfilter0> transform could not transform video/x-h264, stream-format=(string)byte-stream, alignment=(string)nal, width=(int)1196, height=(int)720, framerate=(fraction)0/1, parsed=(boolean)true, profile=(string)baseline, level=(string)3.1 in anything we support

GStreamer 1.8.3
VA-API version: 0.39 (libva 1.7.1)
Intel i965 driver for Intel(R) Haswell Desktop - 1.7.1

Version: 1.8.3