Don't use config option sqlite_db
Don't use config option sqlite_db

Config option sqlite_db is deprecated in
0a1bae9859079fb21a03716be947c5f1da6db0a2, and we test database
with sqlite in memory mode [1] as below:

CONF.set_default('connection', "sqlite://", group='database')

and never use config option sqlite_db, so don't need override its
default value.

[1]http://docs.sqlalchemy.org/en/rel_1_0/core/engines.html#sqlite

Change-Id: Ic1363f7464e9b81d65d74fc30b525d0bd06103ed

cwolferh/heat-scratch,noironetworks/heat,openstack/heat,openstack/heat,cwolferh/heat-scratch,noironetworks/heat