Thanks a lot for the informative bug report.
It's not just mysqldump that is the problem, this will break 3rd-party and user scripts as well that rely on the output of SHOW SLAVE STATUS.
The patch 1a057a9 is wrong and needs to be reverted. The output of SHOW SLAVE STATUS must not be changed except to add additional rows at the end, to preserve backwards compatibility.
It's particularly embarrassing to see a change like this go in and break backwards compatibility not just with user's and 3rd-party's scripts, but with a command-line utility mysqldump included with the MariaDB source code itself 
Thanks a lot for the informative bug report.
It's not just mysqldump that is the problem, this will break 3rd-party and user scripts as well that rely on the output of SHOW SLAVE STATUS.
The patch 1a057a9 is wrong and needs to be reverted. The output of SHOW SLAVE STATUS must not be changed except to add additional rows at the end, to preserve backwards compatibility.
It's particularly embarrassing to see a change like this go in and break backwards compatibility not just with user's and 3rd-party's scripts, but with a command-line utility mysqldump included with the MariaDB source code itself