Unbroke setup.py

--HG--
branch : trunk
diff --git a/setup.py b/setup.py
index 377a1c3..698934f 100644
--- a/setup.py
+++ b/setup.py
@@ -65,7 +65,7 @@
 # ignore the old '--with-speedups' flag
 try:
     speedups_pos = sys.argv.index('--with-speedups')
-except IndexError:
+except ValueError:
     pass
 else:
     sys.argv[speedups_pos] = '--with-debugsupport'