Remove parentheses of return.

Since return is inconsistent, I removed unnecessary parentheses and
unified them.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4541)
diff --git a/ssl/d1_msg.c b/ssl/d1_msg.c
index 35a510d..5906e88 100644
--- a/ssl/d1_msg.c
+++ b/ssl/d1_msg.c
@@ -17,7 +17,7 @@
     if (SSL_in_init(s) && !ossl_statem_get_in_handshake(s)) {
         i = s->handshake_func(s);
         if (i < 0)
-            return (i);
+            return i;
         if (i == 0) {
             SSLerr(SSL_F_DTLS1_WRITE_APP_DATA_BYTES,
                    SSL_R_SSL_HANDSHAKE_FAILURE);