Bug 24413: Do not remove the restrictions from AddReturn

Bug 24413: Do not remove the restrictions from AddReturn

As we are now removing them from MarkIssueReturned they should not be
removed from AddReturn as well.
Also I think this will fix a regression, if $doreturn is not set (in
case the item is withdrawn and BlockReturnOfWithdrawnItems or the item
is lost and BlockReturnOfLostItems, and other specific cases).

Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>