Only assign newDef when we have a new def.

While playing around with def/newDef with the qemu code,
I noticed that newDef was *always* getting set to a value,
even when I didn't redefine the domain.  I think the problem
is the virDomainLoadConfig is always doing virDomainAssignDef
regardless of whether the domain already exists in the hashtable.
In turn, virDomainAssignDef is assigning the definition (which
is actually a duplicate) to newDef.  Fix this so that newDef stays
NULL until we actually have a new def.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

src/conf/domain_conf.c

@@ -6151,22 +6151,25 @@ static virDomainObjPtr virDomainLoadConfig(virCapsPtr caps,
 
     if ((configFile = virDomainConfigFile(configDir, name)) == NULL)
         goto error;
-    if ((autostartLink = virDomainConfigFile(autostartDir, name)) == NULL)
-        goto error;
-
-    if ((autostart = virFileLinkPointsTo(autostartLink, configFile)) < 0)
-        goto error;
-
     if (!(def = virDomainDefParseFile(caps, configFile,
                                       VIR_DOMAIN_XML_INACTIVE)))
         goto error;
 
-    if ((dom = virDomainFindByName(doms, def->name))) {
-        virDomainObjUnlock(dom);
-        dom = NULL;
-        newVM = 0;
+    /* if the domain is already in our hashtable, we don't need to do
+     * anything further
+     */
+    if ((dom = virDomainFindByUUID(doms, def->uuid))) {
+        VIR_FREE(configFile);
+        virDomainDefFree(def);
+        return dom;
     }
 
+    if ((autostartLink = virDomainConfigFile(autostartDir, name)) == NULL)
+        goto error;
+
+    if ((autostart = virFileLinkPointsTo(autostartLink, configFile)) < 0)
+        goto error;
+
     if (!(dom = virDomainAssignDef(caps, doms, def, false)))
         goto error;