debrain broken version check

Perhaps not an ideal fix, but wanted to at least raise the issue in this PR. Was getting

    ==> rel (generate)
    ERROR: Reltool support requires at least reltool-0.5.2; this VM is using reltool

As it turns out, `ReltoolVsn` was just `reltool` for my built-from-src OTP 17.0 

(Bonus inclusion: trailing whitespace my editor found and excised)