Perfom the fetchjoin before the nil removal.
Perfom the fetchjoin before the nil removal.

This should fix test insert_into_unique_column.SF-2075180 in default branch

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