tools: proto-only nexthops default

In cumulus, we set proto-only nexthops by default.
The frr-reload script needs to ignore this when
removing config like it does for other default configs.

Ticket: CM-30002
Signed-off-by: Stephen Worley <sworley@cumulusnetworks.com>

tools/frr-reload.py

@@ -1682,6 +1682,7 @@ def ignore_unconfigurable_lines(lines_to_add, lines_to_del):
                     "username",
                     "password",
                     "line vty",
+                    "zebra nexthop proto only",
                     "service integrated-vtysh-config",
                 ]
             ]