Remove `ifdef` check for an OpenSSL version (0.9.6) we don't support (GH-6807)

(cherry picked from commit f0422421)
Co-authored-by: Alex Gaynor <alex.gaynor@gmail.com>

Modules/_ssl.c

@@ -919,11 +919,8 @@ newPySSLSocket(PySSLContext *sslctx, PySocketSockObject *sock,
         BIO_up_ref(outbio->bio);
         SSL_set_bio(self->ssl, inbio->bio, outbio->bio);
     }
-    mode = SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER;
-#ifdef SSL_MODE_AUTO_RETRY
-    mode |= SSL_MODE_AUTO_RETRY;
-#endif
-    SSL_set_mode(self->ssl, mode);
+    SSL_set_mode(self->ssl,
+                 SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER | SSL_MODE_AUTO_RETRY);
 
     if (server_hostname != NULL) {
         if (_ssl_configure_hostname(self, server_hostname) < 0) {