crypto: return the retval of HMAC_Update

Fixes coverity scan issue 55489.

PR-URL: nodejs#10891
Reviewed-By: Ben Noordhuis <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: Brian White <[email protected]>

Author: tmeisenh

src/node_crypto.cc

@@ -3693,8 +3693,8 @@ void Hmac::HmacInit(const FunctionCallbackInfo<Value>& args) {
 bool Hmac::HmacUpdate(const char* data, int len) {
   if (!initialised_)
     return false;
-  HMAC_Update(&ctx_, reinterpret_cast<const unsigned char*>(data), len);
-  return true;
+  int r = HMAC_Update(&ctx_, reinterpret_cast<const unsigned char*>(data), len);
+  return r == 1;
 }