e2e: use error wrapping with %w

The recently introduced failure handling in ExpectNoError depends on error
wrapping: if an error prefix gets added with `fmt.Errorf("foo: %v", err)`, then
ExpectNoError cannot detect that the root cause is an assertion failure and
then will add another useless "unexpected error" prefix and will not dump the
additional failure information (currently the backtrace inside the E2E
framework).

Instead of manually deciding on a case-by-case basis where %w is needed, all
error wrapping was updated automatically with

    sed -i "s/fmt.Errorf\(.*\): '*\(%s\|%v\)'*\",\(.* err)\)/fmt.Errorf\1: %w\",\3/" $(git grep -l 'fmt.Errorf' test/e2e*)

This may be unnecessary in some cases, but it's not wrong.

test/e2e/framework/websocket/websocket_util.go

@@ -40,7 +40,7 @@ func (rt *extractRT) RoundTrip(req *http.Request) (*http.Response, error) {
 func OpenWebSocketForURL(url *url.URL, config *restclient.Config, protocols []string) (*websocket.Conn, error) {
 	tlsConfig, err := restclient.TLSConfigFor(config)
 	if err != nil {
-		return nil, fmt.Errorf("Failed to create tls config: %v", err)
+		return nil, fmt.Errorf("Failed to create tls config: %w", err)
 	}
 	if url.Scheme == "https" {
 		url.Scheme = "wss"
@@ -49,11 +49,11 @@ func OpenWebSocketForURL(url *url.URL, config *restclient.Config, protocols []st
 	}
 	headers, err := headersForConfig(config, url)
 	if err != nil {
-		return nil, fmt.Errorf("Failed to load http headers: %v", err)
+		return nil, fmt.Errorf("Failed to load http headers: %w", err)
 	}
 	cfg, err := websocket.NewConfig(url.String(), "http://localhost")
 	if err != nil {
-		return nil, fmt.Errorf("Failed to create websocket config: %v", err)
+		return nil, fmt.Errorf("Failed to create websocket config: %w", err)
 	}
 	cfg.Header = headers
 	cfg.TlsConfig = tlsConfig