Fix autoloader regression

Classes from core are not autoloaded anymore.
Check password recovery or avatars for instance.

>not a callable action
#0 /home/deo/public_html/office/lib/base.php(650): OC_Router->match('/avatar/Deo/32')
#1 /home/deo/public_html/office/index.php(30): OC::handleRequest()
#2 {main}

@DeepDiver1975 @icewind1991 @kabum @bantu