Update recipe__create_rt_graph.py

I tried to use this for Example 1-15 from "21 Recipes for Mining Twitter" but I got the following error message:

>>> from recipe__create_rt_graph import create_rt_graph
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/thomasernste/src/github-pip-install/recipe__create_rt_graph.py", line 62
    len(nx.connected_components(g.to_undirected()))
    ^
IndentationError: unexpected indent

So I'm not sure if this attempt at an edit will work or be seen, but I have done what I think is the necessary edit to make this work.