Copy ecdsa_meth in EC_KEY_copy.

Change-Id: Ia97e76d6e5a5dc216a05741864c3d59b50d855bd
Reviewed-on: https://boringssl-review.googlesource.com/4750
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/ec/ec_key.c b/crypto/ec/ec_key.c
index 3652ba5..348ec46 100644
--- a/crypto/ec/ec_key.c
+++ b/crypto/ec/ec_key.c
@@ -201,6 +201,11 @@
     }
   }
   /* copy method/extra data */
+  if (src->ecdsa_meth) {
+      METHOD_unref(dest->ecdsa_meth);
+      dest->ecdsa_meth = src->ecdsa_meth;
+      METHOD_ref(dest->ecdsa_meth);
+  }
   CRYPTO_free_ex_data(&g_ex_data_class, dest, &dest->ex_data);
   if (!CRYPTO_dup_ex_data(&g_ex_data_class, &dest->ex_data,
                           &src->ex_data)) {