qemu_hotplug: Assume chardev alias always exists in qemuDomainDetachChrDevice

The @tmpChr is looked up in domain definition based on user
provided chardev XML. Therefore, the alias must have been
allocated already when domain was started up.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

src/qemu/qemu_hotplug.c

@@ -6144,11 +6144,6 @@ int qemuDomainDetachChrDevice(virQEMUDriverPtr driver,
     guestfwd = tmpChr->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_CHANNEL &&
                tmpChr->targetType == VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_GUESTFWD;
 
-    if (!tmpChr->info.alias && qemuAssignDeviceChrAlias(vmdef, tmpChr, -1) < 0)
-        goto cleanup;
-
-    sa_assert(tmpChr->info.alias);
-
     if (!async && !guestfwd)
         qemuDomainMarkDeviceForRemoval(vm, &tmpChr->info);