If rand::OsRng fails, switch to EntropyRng (potential sidedoor)

[samyk]

oee/oee.rs

Line 36 in 6bb7cdf

let mut csprng = match rand::OsRng::new() {

Potential sidedoor revealed.

"You may prefer to use EntropyRng instead of OsRng. Is is unlikely, but not entirely theoretical, for OsRng to fail. In such cases EntropyRng falls back on a good alternative entropy source."
https://docs.rs/rand/0.5.0-pre.0/rand/os/index.html