[pitivi] pipeline: Don't release the lock twice.

[Edward Hervey <edwardrv src gnome org>]

commit 7a40dc0ccdfbcf345fccb1330a62fb4cb0ccdade
Author: Edward Hervey <bilboed bilboed com>
Date:   Tue May 18 13:34:33 2010 +0200

    pipeline: Don't release the lock twice.
    
    If an exception is raised in the try block, it will go in the except
    statement (which will release the lock) and then ... we try to
    release it again.

 pitivi/pipeline.py |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/pipeline.py b/pitivi/pipeline.py
index 00a8929..ea1ad7e 100644
--- a/pitivi/pipeline.py
+++ b/pitivi/pipeline.py
@@ -903,7 +903,8 @@ class Pipeline(Signallable, Loggable):
                 action.streamRemoved(factory, stream)
         except:
             self._lock.release()
-        self._lock.release()
+        else:
+            self._lock.release()
 
     def _connectToPadSignals(self, bin):
         # Listen on the given bin for pads being added/removed