Midi output broken on develop

[laenzlinger]

When compiling against the current development branch the MIDI output does not work

This can be for example tested with the plugin Example Fitfth (Rust Edition) for docs/fifth

How to reproduce:

1. jackd -d alsa
2. jalv http://lv2plug.in/plugins/eg-fifths
3. jack_midi_dump
4. jack_midiseq Sequencer 24000 0 60 8000 12000 63 8000
5. jack_connect Sequencer:out "Example Fifths (Rust Edition):in"
6. jack_connect "Example Fifths (Rust Edition):out" midi-monitor:input

The above experiment works on b6d02f3 but does not work on 44aac00 (current develop branch)

I did some debugging with rust-gdb and collected the raw buffer of a Note On Midi message in jalv

0x7fe4000b60:    0x00008000    0x00000021    0x00000027    0x00000000
0x7fe4000b70:    0x00008000    0x00000021    0x0000001b    0x00000027
0x7fe4000b80:    0x00000037    0x00000000    0x00000064    0x00000000
0x7fe4000b90:    0x00000003    0x0000000d    0x007f2490 

compared to a working message one can see that there are two additional words 0x00008000 0x00000021 compared to a working sequence atom message

0x7fe4008ba0:    0x00008000    0x00000021    0x00000027    0x00000000
0x7fe4008bb0:    0x0000001b    0x00000027    0x00000037    0x00000000
0x7fe4008bc0:    0x00000064    0x00000000    0x00000003    0x0000000d
0x7fe4008bd0:    0x007f3080