flvdemux: set sample rate to 8KHz for G.711 audio
flvdemux always sets sample rate to 5512 Hz if AudioTag contains codec_type 7(x-alaw) or 8(x-mulaw), audio pad caps template contains sampling rates which are not possible for G.711 audio.
Most of G.711 elements GStreamer has support 8KHz only (mulawdec, alawdec, rtppcmapay/rtppcmupay).
Edited by codinho