STILL BAD, DO NOT PR/Push

TO TEST: use vmi_shutdown_singlestep on a recent system with glib asserts enabled

Bugfix - libvmi/events.c : vmi_shutdown_single_step should use g_hash_table_foreach_steal rather than g_hash_table_foreach_remove as the passed function will modify the SS events hashtable, which is forbidden by glib API documentation and throws an assert as a result.