Clean up the use of ERR_print_errors() in apps.c and in four apps

Clean up the use of ERR_print_errors() in apps.c and in four apps

Also make sure that all error messages in apps.c consistently begin upper-case.
Changed files: apps/lib/apps.c and apps/{req.c,s_client.c,s_server.c,x509.c}

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/4940)