fix rel paths

Author: chriddyp

plotly/tests/test_core/test_offline/test_offline.py

@@ -17,5 +17,5 @@ def test_downloading_file_saves_it_to_the_disk(self):
                         '24cd2e4e62ceea79e6e790b3a2c94cda63510ede/test.js')
 
         plotly.offline.download_plotlyjs(dummy_js_url)
-        assert (os.path.isfile(plotly.offline.PLOTLY_OFFLINE_BUNDLE) is
+        assert (os.path.isfile(plotly.offline.offline.PLOTLY_OFFLINE_BUNDLE) is
                 True)