avoid some clippy warnings

src/backup/crypt_config.rs

@@ -67,8 +67,7 @@ impl CryptConfig {
         let mut hasher = openssl::sha::Sha256::new();
         hasher.update(&self.id_key);
         hasher.update(data);
-        let digest = hasher.finish();
-        digest
+        hasher.finish()
     }
 
     pub fn data_signer(&self) -> openssl::sign::Signer {

src/backup/crypt_reader.rs

@@ -67,25 +67,23 @@ impl <R: BufRead> Read for CryptReader<R> {
             if count > buf.len() {
                 buf.copy_from_slice(&outbuf[..buf.len()]);
                 self.small_read_buf = outbuf[buf.len()..count].to_vec();
-                return Ok(buf.len());
+                Ok(buf.len())
             } else {
                 buf[..count].copy_from_slice(&outbuf[..count]);
-                return Ok(count);
+                Ok(count)
             }
+        } else if data.len() == 0 { // EOF
+            let rest = self.crypter.finalize(buf)?;
+            self.finalized = true;
+            Ok(rest)
         } else {
-            if data.len() == 0 { // EOF
-                let rest = self.crypter.finalize(buf)?;
-                self.finalized = true;
-                return Ok(rest)
-            } else {
-                let mut read_size = buf.len() - self.block_size;
-                if read_size > data.len() {
-                    read_size = data.len();
-                }
-                let count = self.crypter.update(&data[..read_size], buf)?;
-                self.reader.consume(read_size);
-                return Ok(count)
+            let mut read_size = buf.len() - self.block_size;
+            if read_size > data.len() {
+                read_size = data.len();
             }
+            let count = self.crypter.update(&data[..read_size], buf)?;
+            self.reader.consume(read_size);
+            Ok(count)
         }
     }
 }

src/backup/key_derivation.rs

@@ -176,16 +176,15 @@ pub fn load_and_decrtypt_key(path: &std::path::Path, passphrase: &dyn Fn() -> Re
 
         let cipher = openssl::symm::Cipher::aes_256_gcm();
 
-        let decr_data = openssl::symm::decrypt_aead(
+        openssl::symm::decrypt_aead(
             cipher,
             &derived_key,
             Some(&iv),
             b"", //??
             &enc_data,
             &tag,
-        ).map_err(|err| format_err!("Unable to decrypt key - {}", err))?;
+        ).map_err(|err| format_err!("Unable to decrypt key - {}", err))?
 
-        decr_data
     } else {
         raw_data
     };