run test:ui in CI Server on only Ruby 2.0 (#12822)

UI tests fails randomly on Ruby 1.9.3.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11844 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/tasks/ci.rake

@@ -23,7 +23,7 @@ namespace :ci do
   desc "Build Redmine"
   task :build do
     Rake::Task["test"].invoke
-    Rake::Task["test:ui"].invoke if RUBY_VERSION >= '1.9.3'
+    Rake::Task["test:ui"].invoke if RUBY_VERSION >= '2.0.0'
   end
 
   desc "Finish the build"