fixes size of document in case the server doesn't give the size in the header

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@7929 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/crawler/retrieval/Response.java

@@ -242,7 +242,7 @@ public class Response {
     }
 
     public long size() {
-        if (this.responseHeader != null) {
+        if (this.responseHeader != null && this.responseHeader.getContentLengthLong() != -1) {
             // take the size from the response header
             return this.responseHeader.getContentLengthLong();
         }