osd: add a default value for 'default' in crush_rules
osd: add a default value for 'default' in crush_rules

Let's default to `False` for the `default` attribute in `crush_rules`
variable.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1797774

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>

ceph/ceph-ansible,ceph/ceph-ansible