Add test for tempest run with a whitelist file
Add test for tempest run with a whitelist file

This commit adds a functional test for tempest run with the
--whitelist-file flag to the tempest unit test suite. This will verify
that the whitelist-file argument is being honored correctly and only the
tests matching the regexes in there are being run.

Change-Id: I1935d26ba2a6f761cb2cdc6a129a0008659cad13

openstack/tempest,openstack/tempest,cisco-openstack/tempest,masayukig/tempest,masayukig/tempest,cisco-openstack/tempest