monetdbbincopy: fixup misc things
monetdbbincopy: fixup misc things

I didn't expect this script to get slightly mutated and put into the
public when I passed on my quick proof-of-concept.  Remove some bogus,
add some defences, not yet quite ok, though.

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