set language en to test_label_for at test/unit/query_test.rb

Test on CI Server fails.

http://www.redmine.org/builds/logs/build_trunk_sqlite3_ruby-1.9.3-p194_581.html

<pre>
Failure:
  <"Assignee">("US-ASCII") expected but was
  <"Assigné à">("UTF-8").
test_label_for(QueryTest)
test/unit/query_test.rb:860:in `test_label_for'
</pre>

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@10249 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/unit/query_test.rb

@@ -18,6 +18,8 @@
 require File.expand_path('../../test_helper', __FILE__)
 
 class QueryTest < ActiveSupport::TestCase
+  include Redmine::I18n
+
   fixtures :projects, :enabled_modules, :users, :members,
            :member_roles, :roles, :trackers, :issue_statuses,
            :issue_categories, :enumerations, :issues,
@@ -856,6 +858,7 @@ class QueryTest < ActiveSupport::TestCase
   end
 
   def test_label_for
+    set_language_if_valid 'en'
     q = Query.new
     assert_equal 'Assignee', q.label_for('assigned_to_id')
   end