Making DB sanity checking be optional for DB migration

Adding a deprecated option to skip the DB sanity check to db_sync
interface, to give deployer a chance to execute migration script.
Without this change all migration scripts will be blocked before get
execution.

DocImpact

Change-Id: If887ac6b814879a0140dc1065a060233aee7bc82
Partial-Bug: #1279000
Related-Id: I7f271d846141ac72dde3fb0d12159b125018eb2c
Signed-off-by: Zhi Yan Liu <zhiyanl@cn.ibm.com>
Open Juno development

Bump preversion to 2014.2 to formally open Juno development.
The Icehouse release branch (milestone-proposed) will be cut
from the last commit before this one.

Change-Id: I8fe4b32d60fb7c32e80258f60e2c843b76eb4115
Merge "Making DB sanity checking be optional for DB migration"
Merge "Open Juno development"