[polari] chatView: Fix outgoing check when acknowledging message

[Florian Müllner <fmuellner src gnome org>]

commit 1faedd176c5518808b499e23d8978abdb0b9aaae
Author: Florian Müllner <fmuellner gnome org>
Date:   Sun Jul 31 00:20:46 2016 +0200

    chatView: Fix outgoing check when acknowledging message
    
    All outgoing messages have a pending ID of 0, but it may also be a valid
    ID for incoming ones. So instead of checking whether the ID itself is
    "true-ish" (which isn't the case for 0), test explicitly for undefined.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=769339

 src/chatView.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/chatView.js b/src/chatView.js
index 1f8bf4a..ccb4d96 100644
--- a/src/chatView.js
+++ b/src/chatView.js
@@ -1229,7 +1229,7 @@ const ChatView = new Lang.Class({
                                         notification);
         }
 
-        if (!message.pendingId /* outgoing */ ||
+        if (message.pendingId == undefined /* outgoing */ ||
             (this._active && this._toplevelFocus && this._pending.size == 0))
             this._channel.ack_message_async(tpMessage, null);
         else if (this._needsIndicator)