rake build_agent fails on Debian 9 because retry-on-http-error is not supported
As stated in this comment: #395 (comment 160896), the
--retry-on-http-error flag is not supported by the
wget versions < 1.19. We do use this flag when running
rake build_agent task. We should consider checking the wget version and use it only when wget version is 1.19 or later.