Fix SSL_CTX_set1_curves fuzzer.

SSL_CTX_set1_curves was being called with the size of the input data in
bytes rather than in ints.

BUG=chromium:659361

Change-Id: I90da1c6d60e92423c6b7d9efd744ae70ff589172
Reviewed-on: https://boringssl-review.googlesource.com/11840
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>

fuzz/ssl_ctx_api.cc

@@ -399,7 +399,7 @@ static const std::function<void(SSL_CTX *, CBS *)> kAPIs[] = {
         return;
       }
       SSL_CTX_set1_curves(ctx, reinterpret_cast<const int *>(curves.data()),
-                          curves.size());
+                          curves.size() / sizeof(int));
     },
     [](SSL_CTX *ctx, CBS *cbs) {
       std::string curves;