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/apps/s_client.c b/apps/s_client.c
index 1676696..96bfc15 100644
--- a/apps/s_client.c
+++ b/apps/s_client.c
@@ -3053,7 +3053,7 @@
     bio_c_out = NULL;
     BIO_free(bio_c_msg);
     bio_c_msg = NULL;
-    return (ret);
+    return ret;
 }
 
 static void print_stuff(BIO *bio, SSL *s, int full)