Eliminate an obsolete comment.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2601 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/base.rb

@@ -1520,8 +1520,6 @@ module ActiveRecord #:nodoc:
       # Interpolate custom sql string in instance context.
       # Optional record argument is meant for custom insert_sql.
       def interpolate_sql(sql, record = nil)
-        # Parens in the sql in, e.g., subselects, cause a parse error, so
-        # escape them.
         instance_eval("%@#{sql.gsub('@', '\@')}@")
       end