Raise bad Y auto fix to avoid gameplay issues

Per discussion here, d3eb13d60d (commitcomment-19153154)

Spigot-Server-Patches/0176-Auto-fix-bad-Y-levels-on-player-login.patch

@@ -1,4 +1,4 @@
-From 6b3da1efe41b0866848a471f85b31481ec0e55fc Mon Sep 17 00:00:00 2001
+From 97c0a0a4d4ca2797ea4b10bfad875c777379d66b Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Wed, 21 Sep 2016 23:48:39 -0400
 Subject: [PATCH] Auto fix bad Y levels on player login
@@ -6,17 +6,17 @@ Subject: [PATCH] Auto fix bad Y levels on player login
 Bring down to a saner Y level if super high, as this can cause the server to crash
 
 diff --git a/src/main/java/net/minecraft/server/EntityPlayer.java b/src/main/java/net/minecraft/server/EntityPlayer.java
-index ec3a60a..5db0051 100644
+index ec3a60a..da2b5bb 100644
 --- a/src/main/java/net/minecraft/server/EntityPlayer.java
 +++ b/src/main/java/net/minecraft/server/EntityPlayer.java
 @@ -126,6 +126,7 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
              }
          }
  
-+        if (this.locY > 300) this.locY = 200; // Paper - bring down to a saner Y level if out of world
++        if (this.locY > 300) this.locY = 257; // Paper - bring down to a saner Y level if out of world
          this.getBukkitEntity().readExtraData(nbttagcompound); // CraftBukkit
      }
  
 -- 
-2.9.3
+2.10.0