Backport Workaround for Content-Encoding: None

With the upgrade to curl 7.58.0 in Ubuntu 18.04, the behavior of libcurl has changed when CURLOPT_ACCEPT_ENCODING is set to values other than NULL, and an unknown encoding is used by the server. Previously, curl would decode "gzip" and "deflate" (and now "br") and quietly pass any other, unknown encoding. Now it returns (61) "Unrecognized content encoding type...".

There's a specific workaround, already released in curl 7.59.0 for the problem we encountered after upgrading, namely that some servers use "None" instead of "Identity" to indicate transparent / no encoding:

https://github.com/curl/curl/commit/f886cbfe9c3055999d8174b2eedc826d0d9a54f1

Please backport this patch to Ubuntu 18.04.

Discussion on the libcurl mailing list: https://curl.haxx.se/mail/lib-2018-08/0192.html