qemu: Use correct domain xml flag

Although VIR_DOMAIN_DEF_FORMAT_INACTIVE and VIR_DOMAIN_XML_INACTIVE
happen to have the same value (1<<1), they come from different enums;
and it is nicer to reason about a 'flags' variable if all uses of
that variable are compared against the same enum type.  Messed up in
commit 06f75ff2 (3.8.0).
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

src/qemu/qemu_driver.c

@@ -7357,7 +7357,7 @@ static char
      * ignore the VIR_DOMAIN_XML_UPDATE_CPU flag.
      */
     if (virDomainObjIsActive(vm) &&
-        !(flags & VIR_DOMAIN_DEF_FORMAT_INACTIVE))
+        !(flags & VIR_DOMAIN_XML_INACTIVE))
         flags &= ~VIR_DOMAIN_XML_UPDATE_CPU;
 
     ret = qemuDomainFormatXML(driver, vm, flags);