Check_MK Werk 6938: cmk-update-agent: Handle failing package manager

ID: 6938 Title: cmk-update-agent: Handle failing package manager Component: agents Level: 1 Class: Bug fix Version: 1.6.0i1 This werk fixes two bugs that occur on Unix and Linux when the invoked package manager fails to install an agent package: The agent updater saved the agent hash to its state file immediately before the update takes place. As a result, an agent package got recognized as installed even if its installation failed. (Regression since Check_MK 1.5) Due to inproper handling of the stderr and stdout streams coming from the invoked package manager, the agent updater crashed on a package manager failure instead of forwarding the error messages to the user or log.