don't show password login form in sign-in drop down

app/views/account/_omniauth_login.html.erb

@@ -0,0 +1,32 @@
+<%#-- copyright
+OpenProject is a project management system.
+Copyright (C) 2012-2014 the OpenProject Foundation (OPF)
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License version 3.
+
+OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+Copyright (C) 2006-2013 Jean-Philippe Lang
+Copyright (C) 2010-2013 the ChiliProject Team
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+See doc/COPYRIGHT.rdoc for more details.
+
+++#%>
+
+<div id="nav-login-content">
+  <%= render :partial => 'account/auth_providers' %>
+</div>

lib/redmine/menu_manager/top_menu_helper.rb

@@ -97,9 +97,9 @@ module Redmine::MenuManager::TopMenuHelper
                    :class => 'login',
                    :title => l(:label_login)
 
-    render_drop_down_menu_node(link, :class => 'drop-down last-child') do
+    render_drop_down_menu_node(link, class: 'drop-down last-child') do
       content_tag :ul do
-        render :partial => 'account/login'
+        render_login_partial
       end
     end
   end
@@ -119,6 +119,17 @@ module Redmine::MenuManager::TopMenuHelper
                                :class => 'drop-down last-child'
   end
 
+  def render_login_partial
+    partial =
+      if OmniauthLogin.disable_password_login?
+        'account/omniauth_login'
+      else
+        'account/login'
+      end
+
+    render partial: partial
+  end
+
   def render_module_top_menu_node(items = more_top_menu_items)
     render_drop_down_menu_node link_to(l(:label_modules), "#", :title => l(:label_modules), :class => 'icon5 icon-version'),
                                items,