Loses information about error codes because pa_assert doesn't report them

Assertion 'pthread_mutex_unlock(&m->mutex) == 0' failed at pulsecore/mutex-posix.c:108, function pa_mutex_unlock(). Aborting.
ExceptionHandler::SendContinueSignalToChild sys_write failed:Broken pipe
ExceptionHandler::GenerateDump waitpid failed:No child processes
ExceptionHandler::WaitForContinueSignal sys_read failed:Bad file descriptor
Abort trap

pa_assert loses the info about the error code that pthread_mutex_unlock failed with. Most likely it is EINVAL, but other situations are also possible.

For debuggability please always report error codes for all system functions.