qemu: rename: Forbid renaming domains with managed save image

The code does not handle renaming of the save state file. In addition to
that the resuming code would need to be tweaked to handle the name
change since the XML is extracted from the save image. The easies option
is to make the rename API even less useful by forbiding this.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1314594

src/qemu/qemu_driver.c

@@ -19994,6 +19994,12 @@ static int qemuDomainRename(virDomainPtr dom,
         goto endjob;
     }
 
+    if (vm->hasManagedSave) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("domain with a managed saved state can't be renamed"));
+        goto endjob;
+    }
+
     if (virDomainObjGetState(vm, NULL) != VIR_DOMAIN_SHUTOFF) {
         virReportError(VIR_ERR_OPERATION_INVALID,
                        "%s", _("domain has to be shutoff before renaming"));