switch from failure to anyhow

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/tools/ticket.rs

@@ -1,6 +1,6 @@
 //! Generate and verify Authentification tickets
 
-use failure::*;
+use anyhow::{bail, Error};
 use base64;
 
 use openssl::pkey::{PKey, Public, Private};