To add a "me too" this same problem bit us when updating our 4.5 cluster today.
It will surely hit anyone once their hosted engine updates ansible to 2.16.2, which breaks
the host upgrades until you patch the specific file mentioned by Marco.
In our case, after we'd upgraded the hosted-engine VM, we went through and upgraded
all of the nodes one-by-one including reboots, and then realized after we thought we were
done that none of the packages on the nodes get upgraded at all. From the UI side of
things, you'd think it had worked (hosts goes maintenance, says updating but quickly
goes to rebooting, comes back up and activates showing no updates needed until the next
time you issue "check for upgrades" against it).