macosx: removeallObjects from NSMutableArray before releasing it.

(cherry picked from commit b6a37e5e)
Signed-off-by: Derk-Jan Hartman <hartman@videolan.org>

modules/gui/macosx/misc.m

@@ -134,6 +134,7 @@ static NSMutableArray *blackoutWindows = NULL;
 
 - (void)dealloc
 {
+    [blackoutWindows removeAllObjects];
     [blackoutWindows release];
     [super dealloc];
 }