send netconf session_close RPC only if connection is alive

[efenian]

Connection can be lost from control plane reset or device restart. meta: reset_connection task wll attempt to send a session_close RPC to a dead connection and ncclient will raise an exception preventing the connection socket_path from being closed out.

SUMMARY

Fixes #348

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

netconf connection

ADDITIONAL INFORMATION

meta: reset_connection attempts to close the connection:
https://github.com/ansible/ansible/blob/4cc47307ef2c5f63215f2eb1cffeabdeab1c59d6/lib/ansible/plugins/connection/__init__.py#L379

Which calls the netconf connection close:

ansible.netcommon/plugins/connection/netconf.py

Line 434 in 3185a94

self._manager.close_session()

If the conneciton was lost due to restart, ncclient raises exeption preventing the ansible socket from being closed:
https://github.com/ncclient/ncclient/blob/a641253370c632182a94b58aa53b66993b8c9a63/ncclient/transport/session.py#L257

This checks the connection status before attempting to send the RPC call to close the session.

- junos_facts:

- junos_command:
    commands: request system reboot

# ncclient connection will be lost

- wait_for::
     port: 830
     delay: 300
     timeout: 600
  delegate_to: localhost

# currently fails to close ansible socket
- meta: reset_connection

# existing socket found and ncclient raises exception
- junos_facts:

[NilashishC]

@efenian Thank you for the PR! Could you please add a bugfix changelog as well?
Ref: https://github.com/ansible-collections/ansible.netcommon/pull/670/files#diff-66156adcbe69206fb2a0d534e9dd88ae532d8fd42753f6d86b92c78f8dbc1f05R2