[Bug][zos_fetch]Fixed Unbound Local Error when source doesn't exist

[mayankmani-sde]

SUMMARY

Rationale
The issue was caused by the variable is_member being referenced inside the error-handling block before it was initialized. When a missing source triggered the failure path, is_member had not yet been defined, resulting in an unhandled UnboundLocalError.
Design Decision
To ensure consistent variable initialization and error handling, is_member is now explicitly initialized to False before the try block.
This guarantees that even if an exception is raised before its assignment, the variable remains accessible during failure conditions.

#2357

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

zos_fetch

ADDITIONAL INFORMATION

- name: Fetch file
      zos_fetch:
        src: /tmp/out.txt.nope
        dest: /tmp/fetched
      register: result

    - name: Print result.
      ansible.builtin.debug:
        msg: "{{ result }}"

fatal: [zvm]: FAILED! => {
    "binary": false,
    "changed": false,
    "checksum": null,
    "data_set_type": null,
    "dest": null,
    "encoding": null,
    "msg": "The source '/tmp/out.txt.nope' does not exist or is uncataloged.",
    "rc": 0,
    "src": null,
    "stderr": null,
    "stderr_lines": null,
    "stdout": null,
    "stdout_lines": null
}

[fernandofloresg]

Looks good to me will approve once the SPS pipeline is shared