Fix #7164 About Director reload issue with missing Job's directive

Fix #7164 About Director reload issue with missing Job's directive

Description:
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When a required directive is removed (like the FileSet directive from the Job resource)
and the reload command is issued, the Director process is doing a M_ERROR_TERM.

  10-Dec 14:31 zog8-dir ERROR TERMINATION
    "Fileset" directive in Job "BackupClient1" resource is required, but not found.

Workaround:
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Use bacula-dir -t or breload to validate the configuration before the reload.