prevent install error nokogiri on Ruby < 1.9.2

<pre>
Gem::InstallError: nokogiri requires Ruby version >= 1.9.2.
An error occurred while installing nokogiri (1.6.0), and Bundler cannot continue.
Make sure that `gem install nokogiri -v '1.6.0'` succeeds before bundling.
</pre>
Use CHILIPROJECT_LANG environment var to set lang in default data loader
prevent Redmine::WikiFormatting::MacrosTest fails on Ruby 1.9
Test cleanup.

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extra : source : efa3d95a282c16487a567d2b8653dce344feab37