fix bug update unique keys. The code was not called because unique keys with only one column do not require an index.
fix bug update unique keys. The code was not called because unique keys with
only one column do not require an index.

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