Since [1] was merged, not only openstacklib::poliy::base but also
openstacklib::policy::default is included to manage the policy file.
This change ensure openstacklib::policy::default is executed after
the packages are installed.
[1] ef662d7ebcea48a93d4ba3668376fa664dfa1a0c
Change-Id: If30dd87a2a029c04c8ab86d7e8dc8d0bf2e694f0