Updates hotfix workflow documentation.
Updates hotfix workflow documentation.

Adds a note related to the edge-case in which dual OS images were built
(one off of `develop` and one from the hotdix).

[#106149908](https://www.pivotaltracker.com/story/show/106149908)

Signed-off-by: Corey Innis <c6de6a297c7ba72017894924528d266f693d3f31@pivotal.io>

barthy1/bosh,barthy1/bosh,barthy1/bosh,barthy1/bosh