[empathy] call-observer: return from ObserveChannels() if the channel was already invalidated

[Guillaume Desmottes <gdesmott src gnome org>]

commit d1c3f0d9952f6806da997428d99cce3c8cb62d95
Author: Guillaume Desmottes <guillaume desmottes collabora co uk>
Date:   Tue Mar 8 15:47:26 2011 +0100

    call-observer: return from ObserveChannels() if the channel was already invalidated

 src/empathy-call-observer.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/empathy-call-observer.c b/src/empathy-call-observer.c
index 3fb5adc..8ebb06c 100644
--- a/src/empathy-call-observer.c
+++ b/src/empathy-call-observer.c
@@ -159,6 +159,8 @@ observe_channels (TpSimpleObserver *observer,
     {
       DEBUG ("The channel has already been invalidated: %s",
           error->message);
+
+      tp_observe_channels_context_fail (context, error);
       return;
     }