Update PlayerCollectionList.java

prevents a stack overflow 
{
2013-06-28 21:59:31 [INFO] [STDERR]     at logisticspipes.utils.PlayerCollectionList.size(PlayerCollectionList.java:42)
2013-06-28 21:59:31 [INFO] [STDERR]     at java.util.AbstractList$Itr.hasNext(Unknown Source)
2013-06-28 21:59:31 [INFO] [STDERR]     at logisticspipes.utils.PlayerCollectionList.checkPlayers(PlayerCollectionList.java:18)
} repeats