[pkg-go] etcd is marked for autoremoval from testing

[Debian testing autoremoval watch]

etcd 2.3.7+dfsg-5 is marked for autoremoval from testing on 2017-01-06

It is affected by these RC bugs:
846542: etcd: FTBFS in testing (undefined: grpc.SupportPackageIsVersion3)

It (build-)depends on packages with these RC bugs:
845453: golang-github-googleapis-proto-client-go: FTBFS: logging.pb.go:216: undefined: grpc.SupportPackageIsVersion3
846322: golang-google-cloud: FTBFS (undefined: grpc.SupportPackageIsVersion3)