hw wallets: generalise 'minimum_library' for those that provide a version number

electrum/plugin.py

@@ -457,7 +457,8 @@ class DeviceMgr(ThreadJob, PrintError):
         '''Returns a list of DeviceInfo objects: one for each connected,
         unpaired device accepted by the plugin.'''
         if not plugin.libraries_available:
-            raise Exception('Missing libraries for {}'.format(plugin.name))
+            message = plugin.get_library_not_available_message()
+            raise Exception(message)
         if devices is None:
             devices = self.scan_devices()
         devices = [dev for dev in devices if not self.xpub_by_id(dev.id_)]