s_client: fix not to send a command letter of R

Before 1.1.0, this command letter is not sent to a server.

CLA: trivial
(cherry picked from commit bc180cb4887c2e82111cb714723a94de9f6d2c35)

Reviewed-by: Ben Kaduk <kaduk@mit.edu>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8081)