Bug 18173: Remove DB field issues.return

Bug 18173: Remove DB field issues.return

The DB field issues.return has never really been used apparently.
I found the first occurrence of this field in
commit eac3a7b19a8aa7cda34aac396f5093c213a4aa5a
CommitDate: Mon Mar 12 22:43:47 2001 +0000
    Database definition file, checked into cvs to make keeping database
    current easier

Since I did not find any use of this field.
I guess it can be removed safely.

There is no proper test plan here. Just make sure this field has never
been used.

Signed-off-by: Magnus Enger <magnus@libriotech.no>
I have not found any use of issues.return or old_issues.return. In
all my live instances the column is always NULL. Issuing and returning
seems to work as expected after the columns have been removed.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>