Remove clean:development:all

It looks like it was copied from figgy; there's no dataseeder in
pomegranate so this was failing.

lib/tasks/dev.rake

@@ -90,14 +90,5 @@ if Rails.env.development? || Rails.env.test?
         puts "Cleaned up test solr server."
       end
     end
-
-    namespace :development do
-      desc "Delete all development metadata, index, and original/derivative data"
-      task all: :environment do
-        seeder = DataSeeder.new
-        seeder.wipe_metadata!
-        seeder.wipe_files!
-      end
-    end
   end
 end