[Pulp-list] Pulp unittests will now run against separate test database

[John Matthews]

I checked in a change that will let the unit tests run against a separate mongo database, "pulp_unittest".
This allows us to run the unit tests without impacting previous syncs in our dev setup.

The test database name is specified in this file: test/common/test-override-pulp.conf 
[database]
name: pulp_unittest

Please let me know if you see any problems.