Fixing that LEX::sp_add_for_loop_variable() did not initialize pack_flag
Fixing that LEX::sp_add_for_loop_variable() did not initialize pack_flag

This fixes compat/oracle.sp test failure in release builds.

natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2