qemu: Check for user alias collisions in coldplug

https://bugzilla.redhat.com/show_bug.cgi?id=1697676

If an user tries to attach a device with colliding user alias
then we attach it happily and thus leave domain unable to start.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_driver.c

@@ -8647,6 +8647,10 @@ qemuDomainAttachDeviceLiveAndConfig(virDomainObjPtr vm,
                                                 driver->xmlopt, parse_flags)))
             goto cleanup;
 
+        if (virDomainDeviceValidateAliasForHotplug(vm, devConf,
+                                                   VIR_DOMAIN_AFFECT_CONFIG) < 0)
+            goto cleanup;
+
         if (virDomainDefCompatibleDevice(vmdef, devConf, NULL,
                                          VIR_DOMAIN_DEVICE_ACTION_ATTACH,
                                          false) < 0)