HPCC-11114 - Missing user credentials from foreign sub files

Sub files retreived from a foreign super, were not created with
the supers user credentials, consequently actions on those sub
files that expected credentials were using the default user.
Pass user of super to sub file creation.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
HPCC-11114 - remove unhelpful utility ver. of createNew

Remove (internal only) version of createNew and use constructor
directly. Clarifies that the public createNew is only ever called
unnamed and unattached. Name and user credentials are passed by
attach or getFile in case of foreign file.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5613 from jakesmith/hpcc-11114

HPCC-11114 - Missing user credentials from foreign sub files

Reviewed-By: Russ Whitehead <william.whitehead@lexisnexis.com>
Reviewed-By: Gavin Halliday <gavin.halliday@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>