gzip Header disappers after a requests with "max-age=0"

[danielschwab]

Hi!
I am using your lib in version 1.3 and disklrucache 1.2.1 and I have the following issue.

I make request without any extra caching request properties. I get the Response (200).
The file in the cache dir (***.0) has the following line:
Content-Encoding: gzip

Now I reload the same url with the following cache propery: addRequestProperty("Cache-Control", "max-age=0");

I get the Resonse (304) and the result is still correct. But after this request the encoding line in the ***.0 file disappears and when i make another request I get and 304 but the data isn't correct anymore.
I guess it is because the "Content-Encoding: gzip" line disappears.