updating the agent image to use the latest version for testing (#3336)
updating the agent image to use the latest version for testing (#3336)


jackfrancis/acs-engine,jackfrancis/acs-engine,jackfrancis/acs-engine,Azure/acs-engine,Azure/acs-engine,Azure/acs-engine,jackfrancis/acs-engine,Azure/acs-engine,Azure/acs-engine,jackfrancis/acs-engine