Once in a million or so, this typo causes a crash when two threads
simultaneously try to call "pa_asynqmsgq_write_poll".
BugLink: http://bugs.launchpad.net/bugs/853560
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Previously we might have dropped messages from IO trheads to the main
thread. This tuend out to be problematic since this cause SHM release
messages to be lost. More visibly however this could cause playback
freezing when moving streams between sinks and removing the old sink
right away.
