[pkg-go] Bug#858241: Dependency on golang-github-coreos-pkg not strict enough

[Sjoerd Simons]

Source: etcd
Version: 3.1.2+dfsg
Severity: serious
Justification: fails to build from source

Looks like etcd needs at least golang-github-coreos-pkg >= 3, when trying to
build against an older versions (as e.g. present in stretch) the build fails
iwth:
  src/github.com/coreos/etcd/tools/functional-tester/etcd-tester/stresser.go:26: cannot use plog (type *capnslog.PackageLogger) as type grpclog.Logger in argument to grpclog.SetLogger:
  *capnslog.PackageLogger does not implement grpclog.Logger (missing Fatalln method)


-- System Information:
Debian Release: 9.0
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, armhf

Kernel: Linux 4.9.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)