lxc: Don't crash by forgetting to ref transient domains

So commit 306b3a85 tried mimicking behaviour of commit 540c339a, but
added a virObjectRef(vm) only after virDomainObjListAdd() in
lxcDomainDefineXMLFlags() and not in lxcDomainCreateXMLWithFiles().
That way undefining a domain that was started with different XML than
defined will leave the domain object in a state with not enough
references to then remove it.  Hence any lxcDomainDestroyFlags() called
afterwards crashes the daemon.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1351057Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

src/lxc/lxc_driver.c

@@ -1247,6 +1247,7 @@ lxcDomainCreateXMLWithFiles(virConnectPtr conn,
                                    VIR_DOMAIN_OBJ_LIST_ADD_CHECK_LIVE,
                                    NULL)))
         goto cleanup;
+    virObjectRef(vm);
     def = NULL;
 
     if (virLXCDomainObjBeginJob(driver, vm, LXC_JOB_MODIFY) < 0) {