Fix parameter name in javadoc

[sergey-melnychuk]

This avoids build failure caused by javadoc error:

actr/src/main/java/com/zakgof/actr/ActorSystem.java:52: error: @param name not found
     * @param scheduler default scheduler for new actors
              ^
actr/src/main/java/com/zakgof/actr/ActorSystem.java:55: warning: no @param for defaultScheduler
    public static ActorSystem create(String name, IActorScheduler defaultScheduler) {

[zakgof]

Thanks!