playbin: decoder fails to activate in push mode != decoder missing

Submitted by Sam Morris

Link to original bug (#552118)

Description

While trying to check bug 546695 against gst-plugins-bad 0.10.8, I opened a MIDI file in totem, and got the 'Search for suitable codec?' dialog box. The following messages were printed to the console:

---

** Message: don't know how to handle audio/midi
** Message: Error: A audio/midi decoder plugin is required to play this stream, but not installed.
gstdecodebin.c(845): close_pad_link (): /play/decodebin0:
No decoder to handle media type 'audio/midi'

** Message: Missing plugin: gstreamer|0.10|totem|audio/midi decoder|decoder-audio/midi (audio/midi decoder)

However, I can play the file just fine if I run 'gst-launch playbin uri=file:///home/sam/som2rabi.mid'.