Remove empty WelcomeHelper module

Signed-off-by: Alex Coles <alex@alexbcoles.com>

app/helpers/welcome_helper.rb

@@ -1,31 +0,0 @@
-#-- encoding: UTF-8
-#-- copyright
-# OpenProject is a project management system.
-# Copyright (C) 2012-2015 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.
-#++
-
-module WelcomeHelper
-end