Update call to deprecated function neobundle#rc()

Neobundle was complaining each time vim started with the following
messages:

[neobundle] neobundle#rc() is deprecated function.
[neobundle] It will be removed in the next version.
[neobundle] Please use neobundle#begin()/neobundle#end() instead.

This patch simply updates the function call as directed by the output.
Merge pull request #21 from tonylegrone/neobundle-update

Update call to deprecated function neobundle#rc()