qemu: ignore query-sev-capabilities errors
qemu: ignore query-sev-capabilities errors

The query-sev-capabilities command fails if SEV is not compiled in,
even though both the command and -object sev-guest are present
in that case :/

Ignore the errors to avoid spamming the logs:
internal error: unable to execute QEMU command 'query-sev-capabilities': SEV feature is not available

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Reviewed-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>
Reviewed-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>

nertpinx/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,libvirt/libvirt,jfehlig/libvirt,zippy2/libvirt,olafhering/libvirt,jardasgit/libvirt,andreabolognani/libvirt,eskultety/libvirt,eskultety/libvirt,nertpinx/libvirt,crobinso/libvirt,nertpinx/libvirt,eskultety/libvirt,fabianfreyer/libvirt,eskultety/libvirt,libvirt/libvirt,olafhering/libvirt,crobinso/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,eskultety/libvirt,andreabolognani/libvirt,zippy2/libvirt,jardasgit/libvirt,jfehlig/libvirt,libvirt/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jfehlig/libvirt,jardasgit/libvirt,crobinso/libvirt,olafhering/libvirt,jardasgit/libvirt,andreabolognani/libvirt,libvirt/libvirt,nertpinx/libvirt,olafhering/libvirt,zippy2/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,zippy2/libvirt,crobinso/libvirt,andreabolognani/libvirt