device: more robust access to keyword exception fields

lib/logitech_receiver/common.py

@@ -253,7 +253,7 @@ class KwException(Exception):
         try:
             return super().__getattr__(k)
         except AttributeError:
-            return self.args[0][k]
+            return self.args[0].get(k)  # was self.args[0][k]
 
 
 """Firmware information."""

lib/solaar/cli/show.py

@@ -234,7 +234,7 @@ def _print_device(dev, num=None):
                     try:
                         v = setting.val_to_string(setting.read(False))
                     except _hidpp20.FeatureCallError as e:
-                        v = e
+                        v = 'HID++ error ' + str(e)
                     print('            %s        : %s' % (setting.label, v))
 
     if dev.online and dev.keys: