fixes #3077 - locale was set to last language by default

[lzap]

So during initialization we are switching current locale into all available
languages to fetch translation of all human readable language names. There
was a bug when default language was set before this loop, so for users in
1.3 RC1 locale was always set to last available language (usually Chinese).

[domcleal]

I think we should additionally make register_human_localenames side-effect free? Can we save the original locale and add an 'ensure' block to restore it at the end?

[domcleal]

Thanks @lzap! Merged as 219879c for Foreman 1.3.