Honor ngs_save_configuration setting when using batch commands

Since [1], we have an option to skip saving configuration on the target
devices.  The batching implementation merged recently did not take into
account this new setting, fix the issue.

[1] https://review.opendev.org/c/openstack/networking-generic-switch/+/868314

Change-Id: I99ea7fcb1f3365c6ecc4c96b6aa8efea3ceb4bf7

Author: jonglezb

networking_generic_switch/batching.py

@@ -444,8 +444,9 @@ def _send_commands(self, device, batches, lock):
                 # tell workers which batches have now been executed
                 self.queue.record_result(batch)
 
-            try:
-                device.save_configuration(net_connect)
-            except Exception:
-                LOG.exception("Failed to save configuration")
-                # Probably not worth failing all batches for this.
+            if device._get_save_configuration():
+                try:
+                    device.save_configuration(net_connect)
+                except Exception:
+                    LOG.exception("Failed to save configuration")
+                    # Probably not worth failing all batches for this.