Patches are attached;
the sample output with 'warning-if-setting-srcpad-caps-fails' one applied:

$ gst-launch-1.0 --gst-debug=3 playbin uri=http://u16b.di.fm:80/di_ambient
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
0:00:00.140571669 10141      0x2619b70 WARN                GST_PADS gstpad.c:3432:gst_pad_peer_query:<typefindelement0:src> pad has no peer
0:00:00.768875073 10141      0x2619b70 WARN                GST_PADS gstpad.c:3432:gst_pad_peer_query:<queue2-0:src> pad has no peer
0:00:00.775417927 10141 0x7f0adc0239e0 WARN                icydemux gsticydemux.c:237:gst_icydemux_add_srcpad:<icydemux0> Failed to set caps on src pad
0:00:00.775472401 10141 0x7f0adc0239e0 WARN               decodebin gstdecodebin2.c:1707:analyze_new_pad:<icydemux0:src> pad has ANY caps, not able to autoplug to anything
0:00:00.898384015 10141      0x2619b70 WARN                 basesrc gstbasesrc.c:2710:gst_base_src_loop:<source> error: Internal data flow error.
0:00:00.898422780 10141      0x2619b70 WARN                 basesrc gstbasesrc.c:2710:gst_base_src_loop:<source> error: streaming task paused, reason not-linked (-1)
ERROR: from element /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0/GstSoupHTTPSrc:source: Internal data flow error.
Additional debug info:
gstbasesrc.c(2710): gst_base_src_loop (): /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0/GstSoupHTTPSrc:source:
streaming task paused, reason not-linked (-1)
ERROR: pipeline doesn't want to preroll.