mantle/platform/gcloud: drop SECURE_BOOT GuestOsFeature
According to
The SECURE_BOOT flag is being deprecated.  It doesn't actually do
anything in the backend now.  Instead, the option to enable secure boot
on an instance resource is being tied to UEFI_COMPATIBLE flag.  So a
user can enable secure boot if the image is tagged with UEFI_COMPATIBLE.
@@ -78,9 +78,6 @@ func (a *API) CreateImage(spec *ImageSpec, overwrite bool) (*compute.Operation,
{
Type: "UEFI_COMPATIBLE",
},
- {
- Type: "SECURE_BOOT",
- },
}
image := &compute.Image{
