Update nitrokey crate to 0.4.0-alpha.0

This is patch marks the first step in the process of updating the
nitrokey dependency to version 0.4. In particular, it integrates with
the first alpha version.
The main change on the nitrocli side accompanying the version bump is
that the nitrokey::CommandError got replaced by a more general
nitrokey::Error which includes the former variant.

Import subrepo nitrokey/:nitrokey at d433189caefe6bd6c88da7fbb1d6e9304353eb83

1 files changed, 16 insertions, 13 deletions

diff --git a/nitrokey/src/config.rs b/nitrokey/src/config.rs
index 2ce6f77..c273792 100644
--- a/nitrokey/src/config.rs
+++ b/nitrokey/src/config.rs
@@ -1,4 +1,7 @@
-use crate::util::CommandError;
+// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
+// SPDX-License-Identifier: MIT
+
+use crate::error::{Error, LibraryError};
 
 /// The configuration for a Nitrokey.
 #[derive(Clone, Copy, Debug, PartialEq)]
@@ -30,21 +33,21 @@ pub struct RawConfig {
 
 fn config_otp_slot_to_option(value: u8) -> Option<u8> {
     if value < 3 {
-        return Some(value);
+        Some(value)
+    } else {
+        None
     }
-    None
 }
 
-fn option_to_config_otp_slot(value: Option<u8>) -> Result<u8, CommandError> {
-    match value {
-        Some(value) => {
-            if value < 3 {
-                Ok(value)
-            } else {
-                Err(CommandError::InvalidSlot)
-            }
+fn option_to_config_otp_slot(value: Option<u8>) -> Result<u8, Error> {
+    if let Some(value) = value {
+        if value < 3 {
+            Ok(value)
+        } else {
+            Err(LibraryError::InvalidSlot.into())
         }
-        None => Ok(255),
+    } else {
+        Ok(255)
     }
 }
 
@@ -66,7 +69,7 @@ impl Config {
 }
 
 impl RawConfig {
-    pub fn try_from(config: Config) -> Result<RawConfig, CommandError> {
+    pub fn try_from(config: Config) -> Result<RawConfig, Error> {
         Ok(RawConfig {
             numlock: option_to_config_otp_slot(config.numlock)?,
             capslock: option_to_config_otp_slot(config.capslock)?,