Fix for Bug#129599

Breakage of BeOS build due to checkin for fix of bug#124042

change
#include nsIFileChannel.h
to
#include nsIFileURL.h

r=cls
a=asa

widget/src/beos/nsFilePicker.cpp

@@ -28,7 +28,7 @@
 #include "nsFilePicker.h"
 #include "nsILocalFile.h"
 #include "nsIURL.h"
-#include "nsIFileChannel.h"
+#include "nsIFileURL.h"
 #include "nsIStringBundle.h"
 #include "nsReadableUtils.h"