HPCC-10228 Roxie should lock subfiles, not just rely on superfile lock

Locking justy the superfile is not enough, especially in the case where the
superfile does not actually exist (but rather is resolved using package file
information.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #5027 from richardkchapman/package-lock-subfiles

HPCC-10228 Roxie should lock subfiles, not just rely on superfile lock

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>