Don't advertise deflate compression support.

There is some misunderstanding on what the "deflate" is, and we can't
reliably decode it in all cases. So, don't advertise support for it and
let servers use gzip (or no compression) instead.

Fixes #11093

src/kits/network/libnetapi/HttpRequest.cpp

@@ -553,6 +553,9 @@ BHttpRequest::_MakeRequest()
 					readByChunks = true;
 
 				BString contentEncoding(fHeaders["Content-Encoding"]);
+				// We don't advertise "deflate" support (see above), but we
+				// still try to decompress it, if a server ever sends a deflate
+				// stream despite it not being in our Accept-Encoding list.
 				if (contentEncoding == "gzip"
 						|| contentEncoding == "deflate") {
 					decompress = true;
@@ -829,10 +832,12 @@ BHttpRequest::_SendHeaders()
 		outputHeaders.AddHeader("Host", host);
 
 		outputHeaders.AddHeader("Accept", "*/*");
-		outputHeaders.AddHeader("Accept-Encoding", "gzip,deflate");
-			// Allow the remote server to send dynamic content by chunks
-			// rather than waiting for the full content to be generated and
-			// sending us data.
+		outputHeaders.AddHeader("Accept-Encoding", "gzip");
+			// Allows the server to compress data using the "gzip" format.
+			// "deflate" is not supported, because there are two interpretations
+			// of what it means (the RFC and Microsoft products), and we don't
+			// want to handle this. Very few websites support only deflate,
+			// and most of them will send gzip, or at worst, uncompressed data.
 
 		outputHeaders.AddHeader("Connection", "close");
 			// Let the remote server close the connection after response since