Merged r16324 from trunk to 3.2-stable.

Merged r16324 from trunk to 3.2-stable.

Gemfile: pin i18n version 0.7.0.

i18n 0.8.0 causes error.

<pre>
Redmine::I18nTest#test_languages_options_should_ignore_locales_without_general_lang_name_key:
I18n::InvalidLocale: "foo" is not a valid locale
    lib/redmine/i18n.rb:58:in `ll'
    lib/redmine/i18n.rb:122:in `block in languages_options'
    lib/redmine/i18n.rb:122:in `map'
    lib/redmine/i18n.rb:122:in `languages_options'
    test/unit/lib/redmine/i18n_test.rb:203:in `test_languages_options_should_ignore_locales_without_general_lang_name_key'
</pre>

git-svn-id: http://svn.redmine.org/redmine/branches/3.2-stable@16326 e93f8b46-1217-0410-a6f0-8f06a7374b81