Changing command to point hardcoded to PBI will break the package on 2.0.x and also will require changes if PBI changes in anyway. IMO, what you could do is to check if /usr/local/sbin/haproxy is a file or a symlink. If it's a file you set command directly to it, if it's a symlink you figure out what is the symlink target, and set command to it. What do you think?