Allow migrating to UNIX socket

We don't allow local migrations for couple of reasons.  The checks for that were
being added throughout the times, but one of the early ones was actually just
checking for the server part of the destination URI.  This check is surpassed by
other checks (host UUID and hostname) and there are also other checks that would
fail when migrating to the same daemon as duplicate guest UUID.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>

src/libvirt-domain.c

@@ -3298,7 +3298,7 @@ virDomainMigrateCheckNotLocal(const char *dconnuri)
 
     if (!(tempuri = virURIParse(dconnuri)))
         goto cleanup;
-    if (!tempuri->server || STRPREFIX(tempuri->server, "localhost")) {
+    if (tempuri->server && STRPREFIX(tempuri->server, "localhost")) {
         virReportInvalidArg(dconnuri, "%s",
                             _("Attempt to migrate guest to the same host"));
         goto cleanup;