Fix crypto_unittests on Windows BoringSSL port.

crypto/signature_creator_openssl.cc

Index: crypto/signature_creator_openssl.cc
diff --git a/crypto/signature_creator_openssl.cc b/crypto/signature_creator_openssl.cc
index 51cb3c3e1b36022ef577908b36aed36ee2cef930..7a1349b5a5a845919f0312ba0cc715c7d7438db5 100644
--- a/crypto/signature_creator_openssl.cc
+++ b/crypto/signature_creator_openssl.cc
@@ -68,9 +68,8 @@ bool SignatureCreator::Sign(RSAPrivateKey* key,
   signature->resize(RSA_size(rsa_key.get()));
 
   unsigned int len = 0;
-  bool success = RSA_sign(ToOpenSSLDigestType(hash_alg), data, data_len,
-                          vector_as_array(signature), &len, rsa_key.get());
-  if (!success) {
+  if (!RSA_sign(ToOpenSSLDigestType(hash_alg), data, data_len,
+                vector_as_array(signature), &len, rsa_key.get())) {
     signature->clear();
     return false;
   }