Fix of previous fix.  Deal with s == sub correctly (that implies s[-1] != '\\').
Fix of previous fix.  Deal with s == sub correctly (that implies s[-1]
!= '\\').

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