Rename "set_name" to "replica_set_name".

Rename the attributes of IsMaster, ServerDescription, TopologyDescription, and
TopologySettings from "set_name" to "replica_set_name" for greater clarity.
Undeprecate message.insert().

In PyMongo 2.6, message.insert was replaced with _do_batched insert. It was
deprecated but not removed in case third-party libraries might rely on it. In
PyMongo 2.7 we implemented the Bulk API (PYTHON-630) and message.insert found a
new use.
Typo in test_host_w_port.
Shorter timeout in connection-failure tests.
Remove TestClientLazyConnectBadSeeds.

It isn't testing anything, and it can interfere with later tests: on Mac,
there's a global getaddrinfo lock. TestClientLazyConnectBadSeeds
starts 10 threads and doesn't join them, so they're still vying for the
lock as the next tests run.
Simplify auth tests, don't create additional root users.

Don't log out the global test client either; keep it logged in as root and
use it to create additional non-root users to test Database.add_user,
authenticate, logout, and so on.