Spam on tracker when installing/uninstalling tools

I tried to unregister a tracker https://github.com/bountysource/core/issues/1009 which failed. All I got is ugly add/remove spam See https://github.com/OpenRA/ra2/issues/43#event-556842333 for instance.

Start with issue #1009 and the linked OpenRA event example to understand the tracker-registration failure and the add/remove spam. Trace the install and uninstall handling that produces those tracker events. Done means reproducing the operation without generating unwanted add/remove activity.

Written by the indexing model from the issue text.