rdma: silly ipv6 bugfix

My bad - but it's very important for us to warn the user that
IPv6 is broken on RoCE in linux right now, until linux releases
a fixed version.
Signed-off-by: NMichael R. Hines <mrhines@us.ibm.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

migration-rdma.c

@@ -920,9 +920,11 @@ static int qemu_rdma_resolve_host(RDMAContext *rdma, Error **errp)
         ret = rdma_resolve_addr(rdma->cm_id, NULL, e->ai_dst_addr,
                 RDMA_RESOLVE_TIMEOUT_MS);
         if (!ret) {
-            ret = qemu_rdma_broken_ipv6_kernel(errp, rdma->cm_id->verbs);
-            if (ret) {
-                continue;
+            if (e->ai_family == AF_INET6) {
+                ret = qemu_rdma_broken_ipv6_kernel(errp, rdma->cm_id->verbs);
+                if (ret) {
+                    continue;
+                }
             }
             goto route;
         }