Fix undefined running_mon
Since commit [1] running_mon introduced, it can be not defined
which results in fatal error [2]. This patch defines default value which
was used before patch [1]
Signed-off-by: Dmitriy Rabotyagov <drabotyagov@vexxhost.com>
[1] https://github.com/ceph/ceph-ansible/commit/
8dcbcecd713b0cd7769d3b4d04ef5c2f15881377
[2] https://zuul.opendev.org/t/openstack/build/
c82a73aeabd64fd583694ed04b947731/log/job-output.txt#14011
(cherry picked from commit
2478a7b94856fc1b4639b4293383f7c3f2ae0f05)