test: tag tests::reboot for tests_disable_ipv6.yml

This test must be tagged tests::reboot because it reboots
the managed node.

Signed-off-by: Rich Megginson <rmeggins@redhat.com>

Author: richm

tests/tests_disable_ipv6.yml

@@ -1,6 +1,8 @@
 ---
 - name: Ensure that the rule runs with IPv6 disabled
   hosts: all
+  tags:
+    - tests::reboot
   gather_facts: false
   tasks:
     - name: Disable IPv6