Use local variable for bedrock generation

Fixes GH-2596.

Spigot-Server-Patches/0417-Generator-Settings.patch

@@ -1,4 +1,4 @@
-From c7b21a27f6c0f9d3fa2dfbd8ad2aa9a42a0363bc Mon Sep 17 00:00:00 2001
+From e57e2a690085cbbb4425fe60ebe69071bea3e195 Mon Sep 17 00:00:00 2001
 From: Byteflux <byte@byteflux.net>
 Date: Wed, 2 Mar 2016 02:17:54 -0600
 Subject: [PATCH] Generator Settings
@@ -19,7 +19,7 @@ index 246bb4b01..29fd49968 100644
 +    }
  }
 diff --git a/src/main/java/net/minecraft/server/ChunkGeneratorAbstract.java b/src/main/java/net/minecraft/server/ChunkGeneratorAbstract.java
-index 096866b2b..0e104c8c1 100644
+index 096866b2b..338b67c3c 100644
 --- a/src/main/java/net/minecraft/server/ChunkGeneratorAbstract.java
 +++ b/src/main/java/net/minecraft/server/ChunkGeneratorAbstract.java
 @@ -198,8 +198,8 @@ public abstract class ChunkGeneratorAbstract<T extends GeneratorSettingsDefault>
@@ -47,7 +47,7 @@ index 096866b2b..0e104c8c1 100644
              if (k < 256) {
                  for (i1 = k + 4; i1 >= k; --i1) {
 -                    if (i1 <= k + random.nextInt(5)) {
-+                    if (i1 <= (getWorld().paperConfig.generateFlatBedrock ? floorHeight : this.k + random.nextInt(5))) { // Paper - Configurable flat bedrock floor
++                    if (i1 <= (getWorld().paperConfig.generateFlatBedrock ? floorHeight : k + random.nextInt(5))) { // Paper - Configurable flat bedrock floor
                          ichunkaccess.setType(blockposition_mutableblockposition.d(blockposition.getX(), i1, blockposition.getZ()), Blocks.BEDROCK.getBlockData(), false);
                      }
                  }