Updates default text for new failure message

Author: craigsdennis

challenge1-top-referrers.ipynb

@@ -865,7 +865,7 @@
        "Traceback (most recent call last):\n",
        "  File \"/Users/craig/Code/scripting/intro-to-pandas/tests/test_cells.py\", line 31, in test_total\n",
        "    \"Whoops I received a different count than I expected, make sure the last line \"\n",
-       "AssertionError: 475 != 152 : Whoops I received a different count than I expected, make sure the last line is the entire resulting DataFrame (not just the head)\n",
+       "AssertionError: 475 != 142 : Whoops I received a different count than I expected, make sure the last line is the entire resulting DataFrame (not just the head)\n",
        "\n",
        "----------------------------------------------------------------------\n",
        "Ran 3 tests in 0.004s\n",