improve the error message printed when a package build fails
improve the error message printed when a package build fails

ruffsl/ros_buildfarm,mistoll/ros_buildfarm,mistoll/ros_buildfarm,mistoll/ros_buildfarm,ros-infrastructure/ros_buildfarm,ruffsl/ros_buildfarm,ruffsl/ros_buildfarm,ros-infrastructure/ros_buildfarm,ros-infrastructure/ros_buildfarm