HPCC-11139 Unitialised-Warning of pszPrivFile

Fix: pointer initiated to NULL.

Signed-off-by: jamienoss <james.noss@lexisnexis.com>
Merge pull request #5636 from jamienoss/issue11139-pszPrivFile-unitialised

HPCC-11139 Unitialised-Warning of pszPrivFile

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>