Important: libvirt security update (Oracle Linux 7)

[5.7.0-21.el7]
- exadata: Fix the validation when defining domain groups (Wim ten Have) [Orabug: 32085856]
- Revert 'qemu: dont take agent and monitor job for shutdown' (Menno Lageman) [Orabug: 32080283]
- Revert 'qemu: dont hold a monitor and agent job for reboot' (Menno Lageman) [Orabug: 32080283]
- Revert 'qemu: dont hold monitor and agent job when setting time' (Menno Lageman) [Orabug: 32080283]
- Revert 'qemu: remove use of qemuDomainObjBeginJobWithAgent()' (Menno Lageman) [Orabug: 32080283]
- qemu: improve error message when guest vcpu count exceeds domain group limit (Menno Lageman) [Orabug: 31985111]
- qemu: Autonomous hugepage acquisition for 2-MiB and 1-GiB guest memoryBacking. (Wim ten Have)
- qemu: Fix a qemuMemReleaseHostHugepages state error (Wim ten Have) [Orabug: 32069203]
- qemu: avoid guest CPU process handling if exadataConfig is disabled (Wim ten Have) [Orabug: 32053696]
- domain_conf: Relax SCSI addr used check (Michal Privoznik) [Orabug: 31386162]
- domain_conf: Make virDomainDeviceFindSCSIController accept virDomainDeviceDriveAddress struct (Michal Privoznik) [Orabug: 31386162]

[5.7.0-20.el7]
- qemu: remove use of qemuDomainObjBeginJobWithAgent() (Jonathon Jongsma) [Orabug: 31990187] {CVE-2019-20485}
- qemu: dont hold monitor and agent job when setting time (Jonathon Jongsma) [Orabug: 31990187] {CVE-2019-20485}
- qemu: dont hold a monitor and agent job for reboot (Jonathon Jongsma) [Orabug: 31990187] {CVE-2019-20485}
- qemu: dont take agent and monitor job for shutdown (Jonathon Jongsma) [Orabug: 31990187] {CVE-2019-20485}
- qemu: agent: set ifname to NULL after freeing (Jan Tomko) [Orabug: 31964426] {CVE-2020-25637}
- rpc: require write acl for guest agent in virDomainInterfaceAddresses (Jan Tomko) [Orabug: 31964426] {CVE-2020-25637}
- rpc: add support for filtering @acls by uint params (Jan Tomko) [Orabug: 31964426] {CVE-2020-25637}
- rpc: gendispatch: handle empty flags (Jan Tomko) [Orabug: 31964426] {CVE-2020-25637}
- qemu: blockcopy: Fix conditions when virStorageSource should be initialized (Peter Krempa) [Orabug: 31517934]
- qemu: blockcopy: Report error on image format detection failure (Peter Krempa) [Orabug: 31517934]