monitor: move json init from OPEN event to init

At some point in the past, the OPEN event was changed to be issued from a
bottom half.  This creates a small window whereas a data callback registered in
init may be invoked before the OPEN event has been issued.

This is reproducible with:

 echo "{'execute': 'qmp_capabilities'}" | qemu-system-x86_64 -M none -qmp stdio

We can fix this for the monitor by moving the parser initialization to init.

The remaining state that is set in OPEN appears harmless.
Reported-by: NDaniel Berrange <berrange@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
(cherry picked from commit 58617a79)

Conflicts:

	monitor.c
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

monitor.c

@@ -4501,13 +4501,13 @@ static void monitor_control_event(void *opaque, int event)
     switch (event) {
     case CHR_EVENT_OPENED:
         mon->mc->command_mode = 0;
-        json_message_parser_init(&mon->mc->parser, handle_qmp_command);
         data = get_qmp_greeting();
         monitor_json_emitter(mon, data);
         qobject_decref(data);
         break;
     case CHR_EVENT_CLOSED:
         json_message_parser_destroy(&mon->mc->parser);
+        json_message_parser_init(&mon->mc->parser, handle_qmp_command);
         break;
     }
 }
@@ -4610,6 +4610,8 @@ void monitor_init(CharDriverState *chr, int flags)
                               monitor_event, mon);
     }
 
+    json_message_parser_init(&mon->mc->parser, handle_qmp_command);
+
     QLIST_INSERT_HEAD(&mon_list, mon, entry);
     if (!default_mon || (flags & MONITOR_IS_DEFAULT))
         default_mon = mon;