[#216] Remove http2 forcing

fasthttp doesn't support http2
which causes errors when we enable it

Signed-off-by: Nikita Zinkevich <n.zinkevich@yadro.com>

cmd/http-gw/server.go

@@ -74,7 +74,6 @@ func newServer(ctx context.Context, serverInfo ServerInfo) (*server, error) {
 
 		ln = tls.NewListener(ln, &tls.Config{
 			GetCertificate: tlsProvider.GetCertificate,
-			NextProtos:     []string{"h2"}, // required to enable HTTP/2 requests in `http.Serve`
 		})
 	}