Fix for a bug reported by Martin:     create table tmp(i integer unique not null,         b integer references tmp(i));     drop table tmp; the drop generated an error that are keys that reference this table. This fix checks for every key if it references the table itself and only complains in case another table is referencing the table.
Fix for a bug reported by Martin:
    create table tmp(i integer unique not null,
        b integer references tmp(i));
    drop table tmp;
the drop generated an error that are keys that reference this table.
This fix checks for every key if it references the table itself and only
complains in case another table is referencing the table.

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb