fix(ssh-add-key): decode byte-string error message

Popen.communicate returns a byte-string. This needs to be decoded first
before passing to the error handler.

Signed-off-by: Felix Moessbauer <[email protected]>
Signed-off-by: Jan Kiszka <[email protected]>

kas/libkas.py

@@ -327,7 +327,7 @@ def ssh_add_key(env, key):
                     stderr=PIPE, env=env)
     (_, error) = process.communicate(input=str.encode(key))
     if process.returncode and error:
-        logging.error('failed to add ssh key: %s', error)
+        logging.error('failed to add ssh key: %s', error.decode('utf-8'))
 
 
 def ssh_cleanup_agent():