Ensure transient def is removed if LXC start fails

When starting a container, newDef is initialized to a
copy of 'def', but when startup fails newDef is never
removed. This cause later attempts to use 'virDomainDefine'
to lose the new data being defined.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 9d2bfc1c)

src/lxc/lxc_process.c

@@ -1184,6 +1184,10 @@ cleanup:
         VIR_FREE(veths[i]);
     }
     if (rc != 0) {
+        if (vm->newDef) {
+            virDomainDefFree(vm->newDef);
+            vm->newDef = NULL;
+        }
         if (priv->monitor) {
             virObjectUnref(priv->monitor);
             priv->monitor = NULL;