Fix 2 warnings

database/src/fs.rs

@@ -478,7 +478,6 @@ impl Database for Filesystem {
     /// Note that this operation may take a long time, and is
     /// generally only useful for testing.
     fn check_consistency(&self) -> Result<()> {
-        use std::collections::HashMap;
         use failure::format_err;
 
         // A cache of all TPKs, for quick lookups.

database/src/lib.rs

@@ -1,6 +1,5 @@
 #![feature(proc_macro_hygiene, plugin, decl_macro)]
 #![recursion_limit = "1024"]
-#![feature(try_from)]
 
 use std::convert::TryFrom;
 use std::path::PathBuf;