SPIGOT-2098: Fix sound effects for 1.9.0 clients

nms-patches/PacketPlayOutNamedSoundEffect.patch

@@ -0,0 +1,21 @@
+--- a/net/minecraft/server/PacketPlayOutNamedSoundEffect.java
++++ b/net/minecraft/server/PacketPlayOutNamedSoundEffect.java
+@@ -38,7 +38,17 @@
+     }
+ 
+     public void b(PacketDataSerializer packetdataserializer) throws IOException {
+-        packetdataserializer.d(SoundEffect.a.a((Object) this.a));
++        // CraftBukkit start
++        if (packetdataserializer.version > 107) {
++            packetdataserializer.d(SoundEffect.a.a(this.a));
++        } else {
++            int id = SoundEffect.a.a(this.a);
++            if (id >= SoundEffect.a.a(SoundEffect.a.get(new MinecraftKey("item.elytra.flying")))) {
++                id--;
++            }
++            packetdataserializer.d(id);
++        }
++        // CraftBukkit end
+         packetdataserializer.a((Enum) this.b);
+         packetdataserializer.writeInt(this.c);
+         packetdataserializer.writeInt(this.d);