Cleanup executed tasks in hashmap

src/me/ryanhamshire/GriefPrevention/CheckForPortalTrapTask.java

@@ -53,5 +53,6 @@ class CheckForPortalTrapTask extends BukkitRunnable
 			return;
 		}
 		player.setPortalCooldown(0);
+        instance.portalReturnTaskMap.remove(player.getUniqueId());
 	}
 }

src/me/ryanhamshire/GriefPrevention/GriefPrevention.java

@@ -3659,6 +3659,7 @@ public class GriefPrevention extends JavaPlugin
 		//Cancel existing rescue task
 		if (portalReturnTaskMap.containsKey(player.getUniqueId()))
 			portalReturnTaskMap.get(player.getUniqueId()).cancel();
+
 		portalReturnTaskMap.put(player.getUniqueId(), task);
 	}
 }