Override search similarity to ignore doc length
Override search similarity to ignore doc length

This should improve search results, since it means we will ignore the
length of the _content field when scoring results.

clojars/clojars-web,tobias/clojars-web,clojars/clojars-web,tobias/clojars-web,ato/clojars-web,clojars/clojars-web,ato/clojars-web,tobias/clojars-web