This happens on Windows when dialing a named pipe (a path which is used by CLI
plugins), in that case some debugging shows:
DEBU[0000] conn is a *winio.win32MessageBytePipe
DEBU[0000] conn is a halfReadCloser: false
DEBU[0000] conn is a halfWriteCloser: true
the raw stream connection does not implement halfCloser
In such cases we can simply wrap with a nop function since closing for read
isn't too critical.
Signed-off-by: Ian Campbell <ijc@docker.com>
8919bbf04d