Make update_db an opt arg in scheduler manager.
Make update_db an opt arg in scheduler manager.

Updates the scheduler manager so that update_db is an optional
argument. This fixes issues when trying to make RPC calls
with the most recent version (1.4) of the scheduler RPC API.

Fixes LP Bug #1035004.

Change-Id: Ib998c0465cead1b8e117a7344557f8ff496c7e40

n0ano/gantt,n0ano/gantt