fix handling of timed out HttpURLClient requests with contentType.ANY

Timed out HttpURLClient requests with contentType: ContentType.ANY (default value) fail with NullPointerException instead of throwing SocketTimeoutException
```groovy
new HttpURLClient(url: 'http://www.google.com').request(timeout: 1)
```
```java
java.lang.NullPointerException
	at groovyx.net.http.ParserRegistry.getAt(ParserRegistry.java:367)
	at groovyx.net.http.HttpURLClient.getparsedResult(HttpURLClient.java:256)
	at groovyx.net.http.HttpURLClient.request(HttpURLClient.java:237)
```