module: replace NativeModule.require

The NativeModule system passes NativeModule.require transparently and so
is unnecessary to call explicitly.

The only one which should have the prefix is the in line 295, where
actually implements a big fs-based module system and actually requires a
native module. That is left unchanged.

PR-URL: https://github.com/joyent/node/pull/9201
Ref: https://github.com/joyent/node/issues/2009


Reviewed-by: Trevor Norris <trev.norris@gmail.com>