try to fix DataCell compilation error, by simply removing the unused variable that causes the problem.
try to fix DataCell compilation error, by simply removing the unused variable that causes the problem.

Mtest shows this change doesn't make the code worse.

@Martin: please double check!

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