fixed ConcurrentModificationException on BeaconManager

[furkanvarol]

I investigated the problem I told before (#116). It seems like 94520a8 caused problem. I have fixed the problem (actually reverted code). Since, ConsumerInfo is not an immutable class, putting the reference of it after changing isConnected to true is unnecessary.

So, it could be in this way:

for (BeaconConsumer consumer : consumers.keySet()) {
    Boolean alreadyConnected = consumers.get(consumer).isConnected;
    if (!alreadyConnected) {
        consumer.onBeaconServiceConnect();
        ConsumerInfo consumerInfo = consumers.get(consumer);
        consumerInfo.isConnected = true;
    }
}

[furkanvarol]

I think I should re-open pr since my work email got mixed as user.email. Sorry for that