• removed all H2*Timeout directives. HTTP/2 uses not the same Timeout and
  KeepAliveTimeout as HTTP/1.1.
• enforcing the Timeout value on read and write operations from the selected
  virtual host (TLS+SNI). httpd was wrongly using the defaults set in the
  base server config.
• add DEBUG logging to see if writing properly returns to catch a connection
  hanger reported in #79