Don't chown qemu saved image back to root after save if dynamic_ownership=0

When dynamic_ownership=0, saved images must be owned by the same uid
as is used to run the qemu process, otherwise restore won't work. To
accomplish this, qemuSecurityDACRestoreSavedStateLabel() needs to
simply return when it's called.

This fix is in response to:

  https://bugzilla.redhat.com/show_bug.cgi?id=661720

src/qemu/qemu_security_dac.c

@@ -533,7 +533,7 @@ qemuSecurityDACRestoreSavedStateLabel(virSecurityDriverPtr drv ATTRIBUTE_UNUSED,
                                       virDomainObjPtr vm ATTRIBUTE_UNUSED,
                                       const char *savefile)
 {
-    if (!driver->privileged)
+    if (!driver->privileged || !driver->dynamicOwnership)
         return 0;
 
     return qemuSecurityDACRestoreSecurityFileLabel(savefile);