Fix wildcards in `debian/rules.in`

GNU Make's built-in shell is old-school Bourne shell, and doesn't
recognize the bash `foo-{bar,baz}`-style wildcards.  (This simple fact
seems to be a steep learning curve for YT.)

Also, use `rm -f` and remove the initial `-` from statements: `rm -f`
doesn't fail if the file doesn't exist, but does fail if the file
exists but can't be removed.  The latter case is a true error that
shouldn't be suppressed.