qemu_hotplug: remove another erroneous qemuDomainDetachExtensionDevice() call

qemuDomainRemoveRNGDevice() calls qemuDomainDetachExtensionDevice().
According to commit 1d1e264f1 that added this code, it should not be
necessary to explicitly remove the zPCI extension device for a PCI
device during unplug, because "QEMU implements an unplug callback
which will unplug both PCI and zPCI device in a cascaded way". In
fact, no other devices call qemuDomainDetachExtensionDevice() during
their qemuDomainRemove*Device() function, so it should be removed from
qemuDomainRemoveRNGDevice as well.

Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>

src/qemu/qemu_hotplug.c

@@ -4884,9 +4884,6 @@ qemuDomainRemoveRNGDevice(virQEMUDriverPtr driver,
 
     qemuDomainObjEnterMonitor(driver, vm);
 
-    if (qemuDomainDetachExtensionDevice(priv->mon, &rng->info) < 0)
-        rc = -1;
-
     if (rc == 0 &&
         qemuMonitorDelObject(priv->mon, objAlias) < 0)
         rc = -1;