Remove two attributes we no longer need

Remove incoming_redirect_links and text_words.  Both are small so they
are unlikely to save much space.

DEPLOYMENT: This will cause [invalid] word counts and change results ordering
unless a link count has been performed with version of Cirrus in master for
the past two weeks.

Change-Id: I4e4c212c93010fb4f27d6d12e3eec9c710f992ec