[wp] use success-only for qualif

src/plugins/wp/register.ml

src/plugins/wp/tests/test_config_qualif

...ns/wp/tests/wp/oracle_qualif/stmtcompiler_test.res.oracle

src/plugins/wp/tests/wp/oracle_qualif/wp_behav.0.res.oracle

src/plugins/wp/tests/wp/oracle_qualif/wp_behav.1.res.oracle

src/plugins/wp/tests/wp/oracle_qualif/wp_strategy.res.oracle

src/plugins/wp/tests/wp/stmtcompiler_test.i

src/plugins/wp/tests/wp/stmtcompiler_test_rela.i

src/plugins/wp/tests/wp/wp_strategy.c

...plugins/wp/tests/wp_acsl/oracle_qualif/arith.1.res.oracle

...wp/tests/wp_acsl/oracle_qualif/assigns_range.1.res.oracle

src/plugins/wp/tests/wp_acsl/oracle_qualif/axioms.res.oracle

...plugins/wp/tests/wp_acsl/oracle_qualif/bitwise.res.oracle

src/plugins/wp/tests/wp_acsl/oracle_qualif/cnf.res.oracle

...ugins/wp/tests/wp_acsl/oracle_qualif/div_mod.2.res.oracle

...gins/wp/tests/wp_acsl/oracle_qualif/init_label.res.oracle

...ns/wp/tests/wp_acsl/oracle_qualif/init_value.1.res.oracle

.../wp/tests/wp_acsl/oracle_qualif/label_escape.1.res.oracle

src/plugins/wp/tests/wp_acsl/oracle_qualif/logic.res.oracle

...ugins/wp/tests/wp_acsl/oracle_qualif/pointer.0.res.oracle