SUNRPC_DEBUG doesn't work on linux 3.3

It's as if the option isn't there.

http://hydra.nixos.org/build/4015233

pkgs/os-specific/linux/kernel/linux-3.3.nix

···
       # Devtmpfs support.
       DEVTMPFS y
 
-      # Easier debug of NFS issues
-      SUNRPC_DEBUG y
-
       ${if kernelPlatform ? kernelExtraConfig then kernelPlatform.kernelExtraConfig else ""}
       ${extraConfig}
     '';