endpoints/getting-started-grpc: remove links to docs
I removed the links to the quickstarts because they use the bookstore-grpc sample and not this one.
This sample demonstrates how to use Google Cloud Endpoints using Go and gRPC.
-For a complete walkthrough, see the following guides:
-
-* [Quickstart with gRPC on Container Engine](https://cloud.google.com/endpoints/docs/quickstart-grpc-container-engine)
-* [Quickstart with gRPC on Compute Engine](https://cloud.google.com/endpoints/docs/quickstart-grpc-compute-engine-docker)
-
## Test the code locally (optional)
Run the backend using `go run`:
