httpc: handle bad Content-Encoding with curl-7.67.0+

libcurl-7.66.0 and older returns CURLE_WRITE_ERROR when a server
responds with unknown or unsupported Content-Encoding (see [1] and [2]).
This was fixed in future libcurl-7.67.0 and proper
CURLE_BAD_CONTENT_ENCODING code will be returned in this case.

We should process the code in the same way as we do for
CURLE_WRITE_ERROR.

[1]: curl/curl#4310
[2]: curl/curl#4449

Closes #4579

Reviewed-by: Alexander Turenko <alexander.turenko@tarantool.org>

src/httpc.c

@@ -446,6 +446,7 @@ httpc_execute(struct httpc_request *req, double timeout)
 	case CURLE_COULDNT_RESOLVE_HOST:
 	case CURLE_COULDNT_CONNECT:
 	case CURLE_WRITE_ERROR:
+	case CURLE_BAD_CONTENT_ENCODING:
 		/* 595 Connection Problem (AnyEvent non-standard) */
 		req->status = 595;
 		req->reason = curl_easy_strerror(req->curl_request.code);