Merge branch 'master' into t

* master:
  go/zodb/zeo: Correctly prefix zLink-related errors with operational context
  go/{zeo,neo}: handshake: Report "unexpected EOF" if peer sends only partial data
  go/{zeo,neo}: Don't tolerate if a packet reads only partially
  go/zodb/fs1: Factor-out noEOF and okEOF into common place (-> internal/xio)