Prevent group names of length < 5 when updating settings

This restriction does not apply to admins.

app/controllers/groups_controller.rb

@@ -16,7 +16,7 @@ class GroupsController < Groups::ApplicationController
   before_action :group_projects, only: [:show, :projects, :activity, :issues, :merge_requests]
   before_action :event_filter, only: [:activity]
 
-  before_filter :validate_name, only: :create
+  before_filter :validate_name, only: [:create, :update]
 
   layout :determine_layout
 
@@ -143,10 +143,15 @@ class GroupsController < Groups::ApplicationController
   end
 
   def validate_name
-    @group = Group.new(group_params)
-    unless @group.path.empty? || @group.path.length > 4 || current_user.is_admin?
+    group = Group.new(group_params)
+    unless group.path.empty? || group.path.length > 4 || current_user.is_admin?
       flash.now[:alert] = 'Path must have at least a length of 5.'
-      render action: "new"
+      if action_name == 'update'
+        render action: 'edit'
+      else
+        @group = group
+        render action: 'new'
+      end
     end
   end
 end