Fix a few clippy lints

src/config.rs

@@ -196,7 +196,7 @@ impl Config {
             Network::Testnet => daemon_dir.push("testnet3"),
             Network::Regtest => daemon_dir.push("regtest"),
         }
-        let cookie = m.value_of("cookie").map(|s| s.to_owned());
+        let cookie = m.value_of("cookie").map(std::borrow::ToOwned::to_owned);
 
         let mut log = stderrlog::new();
         log.verbosity(m.occurrences_of("verbosity") as usize);

src/daemon.rs

@@ -367,7 +367,7 @@ impl Daemon {
         info!("listing block files at {:?}", path);
         let mut paths: Vec<PathBuf> = glob::glob(path.to_str().unwrap())
             .chain_err(|| "failed to list blk*.dat files")?
-            .map(|res| res.unwrap())
+            .map(std::result::Result::unwrap)
             .collect();
         paths.sort();
         Ok(paths)

src/index.rs

@@ -254,7 +254,7 @@ fn read_indexed_headers(store: &ReadStore) -> HeaderList {
     assert_eq!(
         headers
             .last()
-            .map(|h| h.bitcoin_hash())
+            .map(BitcoinHash::bitcoin_hash)
             .unwrap_or(null_hash),
         latest_blockhash
     );