Fix Specs filename in tutorial code example.
Fix Specs filename in tutorial code example.

The tutorial currently states that specs are in file
BirdNameServiceImpl.scala. Changed this to BirdNameServiceSpec.scala.

chintootech/scala-bootstrapper,wuqiangxjtu/scala-bootstrapper,chintootech/scala-bootstrapper,fizx/scala-bootstrapper,chintootech/scala-bootstrapper,hydro2k/scala-bootstrapper,twitter/scala-bootstrapper,fizx/scala-bootstrapper,twitter/scala-bootstrapper,hydro2k/scala-bootstrapper,wuqiangxjtu/scala-bootstrapper,hydro2k/scala-bootstrapper,wuqiangxjtu/scala-bootstrapper