JR42992: Change in behavior in FTP plugin between DataStage release 7 and 8 w.r.t interpretation of empty values

FTP stage on IS8.7 while reading a CSV file considers the empty value(,,) as empty string("") for VarChar type 
column and 0.00 for Decimal type columns. However v7 treats the empty value as NULL.

RESOLUTION:
The issue is resolved by adding a new environmental variable DSFTP_EMPTY_IS_NULL. If this variable is set to 1 the 
empty values are considered as NULL.