gitattributes: Add new entry to silence whitespace error

Author: petere

.gitattributes

@@ -13,6 +13,7 @@ README.*	conflict-marker-size=32
 *.data						-whitespace
 contrib/pgcrypto/sql/pgp-armor.sql		whitespace=-blank-at-eol
 src/backend/catalog/sql_features.txt		whitespace=space-before-tab,blank-at-eof,-blank-at-eol
+src/backend/utils/Gen_dummy_probes.pl.prolog	whitespace=-blank-at-eof
 
 # Test output files that contain extra whitespace
 *.out					-whitespace