[Bug-apl] UserFunction_header::remove_duplicate_local_var

[Kevin Anderson]

Suggest:

    while(pos < local_vars.size(); ++pos) {
        if (sym == local_vars[pos]) {
            local_vars[pos] = local_vars.back();
            local_vars.pop_back();
        }

    }

instead of:

    for (; pos < local_vars.size(); ++pos) {
        if (sym == local_vars[pos]) {
            local_vars[pos] = local_vars.back();
            local_vars.pop_back();
        }
    }