create_instance passed the loader list where find_uefi_path_for_arch
expects the machine type. The domain capabilities were then read for
the default machine (pc) instead of the chosen one: on a RHEL host a q35
VM was offered /usr/share/OVMF/OVMF_CODE.secboot.fd, which q35 does not
list, instead of /usr/share/edk2/ovmf/OVMF_CODE.fd. The machine type is
passed now.
The page also read dom_caps["loader_enums"] into an unused variable;
on a host without loader support the key is missing and the page failed
with a KeyError. The line is removed.
A unit test covers the call and the host without loader support (it
fails on the previous code). A live test creates a q35 VM with the
offered UEFI firmware, checks that libvirt lists that loader for q35 and
starts the VM; it fails on the previous code.
Comments, docstrings and live test names cited item IDs of a roadmap
that is not part of the repository. They now say what is meant, or
nothing where the sentence stands without them. Test assertions and
behavior are unchanged.
Web form: the cache mode and the UEFI firmware value were checked only
after the disk volume had been created; an invalid one answered 500 and
left the volume. All checks now run before any allocation. Volumes the
request creates are removed on any failure up to the definition; ones
that cannot be removed are reported. After the definition the VM uses
them, so a later failure keeps them.
API: the new volume was never removed when the definition failed, and
the error was a 500. It is removed now and a libvirt error returns 400.
