do not set cookie header if not available for node client

`Cookie: \r\n` or `Cookie: undefined` may cause some backend server exception:
```
Severe:   An exception or error occurred in the container during the request processing
java.lang.IllegalArgumentException
  at org.glassfish.grizzly.http.util.CookieParserUtils.parseClientCookies(CookieParserUtils.java:353)
  at org.glassfish.grizzly.http.util.CookieParserUtils.parseClientCookies(CookieParserUtils.java:336)
  at org.glassfish.grizzly.http.Cookies.processClientCookies(Cookies.java:220)
  at org.glassfish.grizzly.http.Cookies.get(Cookies.java:131)

```