#178 Remove the HOLD data when approving/rejecting submissions

[Ahasuerus]

Remove the HOLD data when approving/rejecting submissions. At this time approved and rejected submissions retain the ID of the moderator who had the submission on hold in the field "sub_holdid". This can present a problem once the ability to "unreject" submissions is implemented.

[Ahasuerus]

Implemented in:

biblio/cancelsubmission.py
mod/hardreject.py
mod/isfdblib.py
mod/reject.py
scripts/remove_old_hold_data.py

Installed in SVN 528 on 2020-05-13. Closing the SR.

[Ahasuerus]

Part 2 - Bug fix:

mod/reject.py

Installed in SVN 530 on 2020-05-13. Keeping the SR closed.