Remove todo with virtual attr inclusion in attr list

[d-m-u]

In service retirement, the line in bundled subtask creation that removed the virtual attributes from the new subtask attributes (#17912) is no longer necessary because #17996, which removes the attributes altogether, has been merged, yay.

[d-m-u]

@miq-bot assign @gmcculloug
@miq-bot add_reviewer @tinaafitz
@miq-bot add_label cleanup

[miq-bot]

Checked commit d-m-u@c195c67 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
1 file checked, 0 offenses detected
Everything looks fine. 🍪

[d-m-u]

@miq-bot add_label hammer/yes

[simaishi]

Hammer backport details:

$ git log -1
commit 1b5cf548d5ed513c4ce09a1cdcc618e5cb5a0f5e
Author: Greg McCullough <gmccullo@redhat.com>
Date:   Wed Sep 26 08:33:45 2018 -0400

    Merge pull request #18019 from d-m-u/removing_hacky_virtual_attrs_todo
    
    Remove todo with virtual attr inclusion in attr list
    
    (cherry picked from commit dc7975fc3047312f7c879428c24e098dd00ceddf)