pass a copy of cfg to FormatConverter.to_serialized() as it modifies …

…original cfg

Signed-off-by: Stepan Blyshchak <stepanb@nvidia.com>

sonic-utilities-data/templates/sonic-cli-gen/config.py.j2

@@ -9,6 +9,7 @@ Source YANG module: {{ source_yang_module }}
 {% endif %}
 """
 
+import copy
 import click
 import utilities_common.cli as clicommon
 import utilities_common.general as general
@@ -41,7 +42,7 @@ def validate_config_or_raise(cfg):
  """
 
  try:
- cfg = sonic_cfggen.FormatConverter.to_serialized(cfg)
+ cfg = sonic_cfggen.FormatConverter.to_serialized(copy.deepcopy(cfg))
  config_mgmt.ConfigMgmt().loadData(cfg)
  except Exception as err:
  raise Exception('Failed to validate configuration: {}'.format(err))