Fix clean-ns duplicating the docstring in ns meta
Fix clean-ns duplicating the docstring in ns meta

Fixes clojure-emacs/clj-refactor.el#185

msgodf/refactor-nrepl,msgodf/refactor-nrepl,Peeja/refactor-nrepl,luxbock/refactor-nrepl,duncanmortimer/refactor-nrepl,grammati/refactor-nrepl,grammati/refactor-nrepl,luxbock/refactor-nrepl,duncanmortimer/refactor-nrepl,clojure-emacs/refactor-nrepl,Peeja/refactor-nrepl,clojure-emacs/refactor-nrepl