Added storage upgrade support and monlist fixes

Closes-Bug: #1381653
Closes-Bug: #1399316
Closes-Bug: #1399570
Closes-Bug: #1400974

Changes done:
1. Added storage upgrade support.
2. HA rabbit host alias got replaced caused failure in rabbitq
   communication. Fixed the above mentioned issue
3. initial mon_list and mon_host not populated during code
   flow change that caused ceph -s to hang. Populated initial
   mon_list and mon_host on ceph.conf
4. Set nofile limit to 102400 on cinder volume init
5. Set Database retry in cinder config

Change done based on review

Tests: 1. Verified storage upgrade from 1.20 to 2.0
       2. HA rabbit host communication works fine with fix #2
       3. initial mon_list/mon_host are populated and no command
          hang issue seen
       4. nofile limit and database retry configs are popluated.

Change-Id: Ia347618fa43845cd505adff8aad1839b447b66c3