use ```Crypt::Blowfish``` if available

Pyrrha currently uses ```Crypt::Blowfish_PP```, but it seems that some LMS installations have the faster ```Crypt::Blowfish```.

See https://github.com/philippe44/lms-deezer/blob/f8155990bc54bbb5fc1ce6d5f30d7851274013f2/ProtocolHandler.pm#L42 for a way to try for ```Blowfish``` but fallback to ```Blowfish_PP```.