Always consume bonemeal when used on a sapling. Fixes BUKKIT-3755

In Minecraft 1.5 saplings do not grow with a single use of bonemeal anymore.
Our code assumes they will and only takes away bonemeal from the player
when the tree grows successfully (not cancelled by a plugin). Instead we
now always remove a bonemeal even if a plugin is the reason a tree didn't
grow as this matches the vanilla logic more closely.

src/main/java/net/minecraft/server/BlockSapling.java

@@ -116,7 +116,11 @@ public class BlockSapling extends BlockFlower {
                     --itemstack.count;
                 }
             }
+        } else if (bonemeal && itemstack != null) {
+            // We always consume bonemeal when trying to grow
+            --itemstack.count;
         }
+
         if (!grownTree) {
             if (flag) {
                 world.setTypeIdAndData(i + i1, j, k + j1, this.id, l, 4);