// If a service account's parent user is not in iamUsersMap, the
			// parent is an STS account. Such accounts may have a policy mapped
			// on the parent user, so we load them. This is not needed for the
			// initial server startup, however, it is needed for the case where
			// the STS account's policy mapping (for example in LDAP mode) may
			// be changed and the user's policy mapping in memory is stale