The volume_tmp_dir and rbd_secret_uuid parameters have a default
value of false, instead of using $::os_service_default. This causes
a broken cinder config if this class is included and non-default
values are not specified for these parameters.
This patch changes the default values to use $::os_service_default
Change-Id: I3ccb5f98348416a6e95849df1d1fe44f79b89be5
Closes-bug: 1530168