phpdoc
version.php files were removed in H4
Use Horde_Registry#appInit() in horde-translation

Otherwise, this fails when retrieving version information for
applications that use $injector or $registry in their _bootstrap()
methods (i.e. IMP 6.2).

I'm assuming the only reason we haven't updated to using appInit() is
because it simply wasn't needed before now - the application just worked.
(AFAICT, horde-translation previouslt required a working version of Horde
installed, so this doesn't change anything).