clang on Linux x86_64 complains about unreachable code.

Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/ssl/ssl_rsa.c b/ssl/ssl_rsa.c
index d046020..723da6e 100644
--- a/ssl/ssl_rsa.c
+++ b/ssl/ssl_rsa.c
@@ -798,7 +798,7 @@
         serverinfo += len;
         serverinfo_length -= len;
     }
-    return 0;                   /* Error */
+    /* Unreachable */
 }
 
 static int serverinfo_srv_parse_cb(SSL *s, unsigned int ext_type,