Fixed wrong link target in docs

Author: passy

docs/index.rst

@@ -30,7 +30,7 @@ or alternatively if you have `pip` installed::
 
 .. _Flask: http://flask.pocoo.org/
 .. _OAuth: http://oauth.net/
-.. _python-oauth2: http://pypi.python.org/pypi/Flask-OAuth2
+.. _python-oauth2: http://pypi.python.org/pypi/oauth2/
 
 Defining Remote Applications
 ----------------------------