From the discussion in #1734, instead of using `env.PROJECT_NAME`,
`steps.strip.outputs.BIN_NAME` could potentially be a better choice as
the filename needs to match the called executable for bash-completion's
on demand loading to work. This `BIN_NAME` needs to stay in sync with
`env.PROJECT_EXECUTABLE` which is replaced in the template, but not
available for the deb build at this stage.
Follow the same route as for the fish/zsh completions for now for the
sake of consistency.
Closes#1733
