Devices/Device.py: report unsupported feature for switchdev corner case

In some cases a query of switchdev info on a device could return an empty
string. When this happens the code expects either legacy or switchdev
mode in the output, otherwise a DeviceError is raised.

The DeviceError causes termination of the machine's device cleanup
process and some devices may be left without deconfiguration.

Since this case should not be considered as a critical issue a
DeviceFeatureNotSupported is raised instead that is accepted during the
deconfiguration.

Signed-off-by: Jan Tluka <[email protected]>

lnst/Devices/Device.py

@@ -935,7 +935,7 @@ def eswitch_mode(self):
         try:
             return m.group(1)
         except AttributeError:
-            raise DeviceError(f"Could not parse device {self.name} eswitch mode")
+            raise DeviceFeatureNotSupported(f"Could not parse device {self.name} eswitch mode")
 
     @eswitch_mode.setter
     def eswitch_mode(self, mode):