add correct database name for credhub

Signed-off-by: JT Archie <jarchie@pivotal.io>

install-pcf/aws/tasks/prepare-rds/task.sh

@@ -19,7 +19,7 @@ GRANT ALL ON locket.* TO '$DB_LOCKET_USERNAME'@'%';
 
 CREATE DATABASE IF NOT EXISTS credhub;
 CREATE USER IF NOT EXISTS '$DB_CREDHUB_USERNAME' IDENTIFIED BY '$DB_CREDHUB_PASSWORD';
-GRANT ALL ON locket.* TO '$DB_CREDHUB_USERNAME'@'%';
+GRANT ALL ON credhub.* TO '$DB_CREDHUB_USERNAME'@'%';
 
 CREATE DATABASE IF NOT EXISTS silk;
 CREATE USER IF NOT EXISTS '$DB_SILK_USERNAME' IDENTIFIED BY '$DB_SILK_PASSWORD';