Add Fedora 32 to supported list and use as fedora-latest

This includes a workaround to a known dnsmasq >= 2.81 issue that
results in unanswered DHCP requests from instances as documented in the
following Neutron bug:

dnsmasq >= 2.81 not responding to DHCP requests with current q-dhcp configs
https://bugs.launchpad.net/neutron/+bug/1896945

For the time being we will attempt to downgrade to 2.80 to avoid this.

Related-Bug: #1896945
Change-Id: I3a760c43956221424926bd9dad0ebe9b28ae2b52
3 files changed