Fix PSK invocation: OpenSSL client

Only s_server has a -nocert option, s_client doesn't. Fixes OpenSSL client
test cases in PSK-only builds.

Signed-off-by: Gilles Peskine <[email protected]>

tests/ssl-opt.sh

@@ -500,7 +500,8 @@ requires_certificate_authentication () {
 
 adapt_cmd_for_psk () {
     case "$2" in
-        *openssl*) s='-psk abc123 -nocert';;
+        *openssl*s_server*) s='-psk abc123 -nocert';;
+        *openssl*) s='-psk abc123';;
         *gnutls-*) s='--pskkey=abc123';;
         *) s='psk=abc123';;
     esac