add_upgrade_boot: small changes from review

repos/system_upgrade/common/actors/addupgradebootentry/libraries/addupgradebootentry.py

@@ -306,14 +306,13 @@ def construct_cmdline_args_for_livemode():
         # @Todo(mhecko): verify this during config scan
         if len(network_fragments) == 1 or network_fragments[0] != 'ip':
             msg = ('The livemode dracut_network configuration value is incorrect - it does not '
-                   'have the form of a key-value cmdline arg: `{0}`.')
+                   'have the form of a key=value cmdline arg: `{0}`.')
             msg = msg.format(livemode_config.dracut_network)
 
             api.current_logger().error(msg)
             raise StopActorExecutionError('Livemode is not configured correctly.', details={'details': msg})
 
-        net_arg_value = network_fragments[1]
-        args['ip'] = net_arg_value
+        args['ip'] = network_fragments[1]
         args['rd.needsnet'] = '1'
 
     autostart_state = '1' if livemode_config.autostart_upgrade_after_reboot else '0'