Previously all of the spec tests for VM Pooler were all together in the specs
directory. However some tests require a working local Redis server to operate
and other instead mock all external dependencies. This commit splits the test
files between unit and integration, where integration tests require a working
Redis instance, and unit tests do not. This commit also removes the root
`vmpooler` directory as it is not required. The tests rake test still operates
correctly.
This commit also adds the mock_redis library for testing for the pool_manager.
