artists: allow members to rename, delete, and undelete artists.

Also allow Members to edit deleted or banned artists. Previously this
was limited in the html, but not in the backend.

app/controllers/artists_controller.rb

@@ -1,7 +1,6 @@
 class ArtistsController < ApplicationController
   respond_to :html, :xml, :json, :js
   before_action :member_only, :except => [:index, :show, :show_or_new, :banned]
-  before_action :builder_only, :only => [:destroy]
   before_action :admin_only, :only => [:ban, :unban]
   before_action :load_artist, :only => [:ban, :unban, :show, :edit, :update, :destroy, :undelete]
 
@@ -61,9 +60,6 @@ class ArtistsController < ApplicationController
   end
 
   def destroy
-    if !@artist.deletable_by?(CurrentUser.user)
-      raise User::PrivilegeError
-    end
     @artist.update_attribute(:is_active, false)
     redirect_to(artist_path(@artist), :notice => "Artist deleted")
   end
@@ -96,8 +92,7 @@ private
   end
 
   def artist_params(context = nil)
-    permitted_params = %i[name other_names other_names_string group_name url_string notes]
-    permitted_params << :is_active if CurrentUser.is_builder?
+    permitted_params = %i[name other_names other_names_string group_name url_string notes is_active]
     permitted_params << :source if context == :new
 
     params.fetch(:artist, {}).permit(permitted_params)