BF: Fix BIPDIR access

bip/utils/__init__.py

@@ -56,4 +56,4 @@ def lockdir(dirname, delay=5):
 def get_data(filename):
     """Return the filename, prefixed with the bip/data/ directory path. """
     filename.replace('/', os.sep)
-    return op.join(bipdir, 'data', filename)
+    return op.join(bip.BIPDIR, 'data', filename)