Don't pass |overhead_len| when testing “open” speed.

It's not needed and some compilers warn about it.

Change-Id: I45ace0db3e9773300387df9e319af4dd5a50d3dc
Reviewed-on: https://boringssl-review.googlesource.com/14011
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

tool/speed.cc

diff --git a/tool/speed.cc b/tool/speed.cc
index edeb236..3e5952f 100644
--- a/tool/speed.cc
+++ b/tool/speed.cc
@@ -251,8 +251,8 @@
     EVP_AEAD_CTX_seal(ctx.get(), out, &out_len, chunk_len + overhead_len,
                       nonce.get(), nonce_len, in, chunk_len, ad.get(), ad_len);
 
-    if (!TimeFunction(&results, [chunk_len, overhead_len, nonce_len, ad_len, in2,
-                                 out, &ctx, &nonce, &ad, out_len]() -> bool {
+    if (!TimeFunction(&results, [chunk_len, nonce_len, ad_len, in2, out, &ctx,
+                                 &nonce, &ad, out_len]() -> bool {
           size_t in2_len;
           return EVP_AEAD_CTX_open(ctx.get(), in2, &in2_len, chunk_len,
                                    nonce.get(), nonce_len, out, out_len,