v6.0.8

Changelog:

8440cca dashboard: set cookie_secure in grafana
8dda6d0 fs2bs: use match filter in selectattr()
b2759c0 fs2bs: fix wrong filter when setting osd_ids
11f953a tests: pull images from cloud.centos.org
e0bcd59 prometheus: enforce osd nodes in templates
01256ff container: conditionnally disable lvmetad
e91e9d6 group_vars: fix default values