qemu: plug memory leak

https://bugzilla.redhat.com/show_bug.cgi?id=656795

* src/qemu/qemu_monitor.c (qemuMonitorFree): Also free the buffer.

src/qemu/qemu_monitor.c

@@ -199,6 +199,7 @@ static void qemuMonitorFree(qemuMonitorPtr mon)
     if (virCondDestroy(&mon->notify) < 0)
     {}
     virMutexDestroy(&mon->lock);
+    VIR_FREE(mon->buffer);
     VIR_FREE(mon);
 }