Fix for one of the problems in bug 3323. When the code decided to use a pre-existing memory map, and the map needed to be extended, the remapping of the extended file failed due to incorrect use of the file name parameters.  We now use MT_mremap to do the extending and remapping.
Fix for one of the problems in bug 3323.
When the code decided to use a pre-existing memory map, and the map
needed to be extended, the remapping of the extended file failed due
to incorrect use of the file name parameters.  We now use MT_mremap to
do the extending and remapping.

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