fix: don't use fence_xvm in tests

The fence_xvm agent / fence-virt package is only available for x86_64
architecture. Using fence_xvm in tests caused they failed on e.g.
aarch64.

Author: idevat

tests/tests_cib_resources_create_and_load_info.yml

@@ -246,7 +246,7 @@
               - name: role
                 value: "{{ __unpromoted }}"
       - id: F1
-        agent: "stonith:fence_xvm"
+        agent: "stonith:fence_kdump"
         copy_operations_from_agent: false
         instance_attrs:
           - attrs: