Add variables for active-passive Galera HA proxy

Backports from icehouse of data mappings to configure Galera HAProxy in
an active-passive model due to compatibility issues between Galera
configured with multiple active writers and certain SQL statements used
in OpenStack code.

Partial-Bug: #1321734
(cherry picked from commit ba8bdadd24e033df3d2feed9bcb383c6b4a28b04)
(cherry picked from commit fa9ac872614e6c535469e3d681e68ccca7e78e93)

Conflicts:
    data/hiera_data/user.full_ha.yaml
    data/hiera_data/user.compressed_ha.yaml