dgram: remove new keyword from errnoException

Reviewed-by: Trevor Norris <trev.norris@gmail.com>
src: require EventEmitter via NativeModule

Fixes a recent change causing test-process-kill-pid.js to fail.

Fixes: 931cbc1 "lib: don't use emitter.listeners(type).length"
Signed-off-by: Trevor Norris <trev.norris@gmail.com>