Bug fix, blob client was not correctly using keys longer than 64 bytes in request signing.

fdbclient/BlobStore.actor.cpp

@@ -873,7 +873,12 @@ Future<BlobStoreEndpoint::ListResult> BlobStoreEndpoint::listBucket(std::string
 std::string BlobStoreEndpoint::hmac_sha1(std::string const &msg) {
 	std::string key = secret;
 
-	// First pad the key to 64 bytes.
+	// Hash key to shorten it if it is longer than SHA1 block size
+	if(key.size() > 64) {
+		key = SHA1::from_string(key);
+	}
+
+	// Pad key up to SHA1 block size if needed
 	key.append(64 - key.size(), '\0');
 
 	std::string kipad = key;