Extra redirect on Language Switching

[xipasduarte]

When using the back-office interface to switch to a new language, there are usually two request:

• 302 with the argument ubb_lang_switch
• 200 resulting page with lang=[locale]

When the language being switched to is the default, there is an extra request in between:

• 302 with the argument ubb_lang_switch
• 301 including an empty argument at the end and no lang=[locale]
• 200 resulting page with lang=[locale]