avidemux: h264 variant itu, regression from 0.10

Submitted by Nicola @drakkan

Link to original bug (#771707)

Description

I have an avi with h264 variant itu, here are the caps:

video/x-h264, variant=(string)itu, framerate=(fraction)120/1, width=(int)320, height=(int)240, codec_data=(buffer)2000000127644014ac2b40a0fd8088000003000800000301e42000000128ee1f2c0000000000000000000000000000000000

this file works fine in 0.10 but in 1.0 give not negotiated, in 0.10 ffdec_h264 show sink caps as:

SINK template: 'sink'
Availability: Always
Capabilities:
video/x-h264
width: [ 16, 4096 ]
height: [ 16, 4096 ]
framerate: [ 0/1, 2147483647/1 ]

while in 1.0 the format are restricted:

SINK template: 'sink'
Availability: Always
Capabilities:
video/x-h264
alignment: au
stream-format: { avc, byte-stream }

if I change avdec_h264 so that gst-inspect shows this:

SINK template: 'sink'
Availability: Always
Capabilities:
video/x-h264

then the file plays fine,

is this acceptable? Do you have other suggestions for a better patch?