Use mattermost v5 module (#1192)

vendor/golang.org/x/net/http2/transport.go

@@ -916,7 +916,7 @@ func commaSeparatedTrailers(req *http.Request) (string, error) {
 		k = http.CanonicalHeaderKey(k)
 		switch k {
 		case "Transfer-Encoding", "Trailer", "Content-Length":
-			return "", &badStringError{"invalid Trailer key", k}
+			return "", fmt.Errorf("invalid Trailer key %q", k)
 		}
 		keys = append(keys, k)
 	}
@@ -1394,13 +1394,6 @@ func (cs *clientStream) awaitFlowControl(maxBytes int) (taken int32, err error)
 	}
 }
 
-type badStringError struct {
-	what string
-	str  string
-}
-
-func (e *badStringError) Error() string { return fmt.Sprintf("%s %q", e.what, e.str) }
-
 // requires cc.mu be held.
 func (cc *ClientConn) encodeHeaders(req *http.Request, addGzipHeader bool, trailers string, contentLength int64) ([]byte, error) {
 	cc.hbuf.Reset()
@@ -1616,6 +1609,7 @@ func (cc *ClientConn) writeHeader(name, value string) {
 }
 
 type resAndError struct {
+	_   incomparable
 	res *http.Response
 	err error
 }
@@ -1663,6 +1657,7 @@ func (cc *ClientConn) streamByID(id uint32, andRemove bool) *clientStream {
 
 // clientConnReadLoop is the state owned by the clientConn's frame-reading readLoop.
 type clientConnReadLoop struct {
+	_             incomparable
 	cc            *ClientConn
 	closeWhenIdle bool
 }
@@ -2479,6 +2474,7 @@ func (rt erringRoundTripper) RoundTrip(*http.Request) (*http.Response, error) {
 // gzipReader wraps a response body so it can lazily
 // call gzip.NewReader on the first call to Read
 type gzipReader struct {
+	_    incomparable
 	body io.ReadCloser // underlying Response.Body
 	zr   *gzip.Reader  // lazily-initialized gzip reader
 	zerr error         // sticky error