Rebalance root disk storage

Experience with real-world deployments has shown that the bulk of the
REC storage requirements are for logs.  This change reworks the LV
allocation on the root disk to reflect this:

- The LV for /home is removed; /home will be on the root filesystem
- The mariadb and swift LVs are significantly reduced in size, as
  neither is used by the RIC or the REC (beyond Keystone)
- the /var/log/audit LV is removed.  /var/log/audit will share space
  with the rest of /var/log
- /var/log is used as the "free hog" lv, taking up any space not used by
  other VGs.

signed-off-by: dave kormann  <davek@research.att.com>
Change-Id: I34502aa156e145c4b30a57f263c106aa89b39073