Fixed PHP-1104: New Replica Set connections hang when secondaries are creating indexes during initialSync

After creating a connection the first thing we must do is do run isMaster().
We cannot run buildinfo or authentication or anything else. It must be isMaster().

This call to ismaster is to check what sort of node we are talking to, and make sure it is
actually a node we are allowed to talk to and can issue commands to (e.g. don't auth to
arbiter, don't send commands to STARTUP nodes, ....).

Unfortunately this means re-introducing the double isMaster() call, once for this sanity
checking and once more for replicaset topology discovery which is done in way different
place and sequence
Differenciate between last_ismaster and a ReplicaSet verification check.

We don't need to do two isMaster() checks for mongos/standalone connections
But we do need it for a ReplicaSet. The second call does the ReplicaSet integrity check,
such as match the ReplicaSet name and who "we" are, along with extracting out tags.

We need a way to be able to run this check even if we have called isMaster() as we don't
cache the actual responses.
Update MongoLog tests
Merge pull request #700 from bjori/PHP-874-ismaster-earlier

Fixed PHP-1104: New Replica Set connections hang when secondaries are cre...

* bjori/PHP-874-ismaster-earlier:
  Update MongoLog tests
  Differenciate between last_ismaster and a ReplicaSet verification check.
  Fixed PHP-1104: New Replica Set connections hang when secondaries are creating indexes during initialSync
Merge branch 'v1.5'

* v1.5:
  Update MongoLog tests
  Differenciate between last_ismaster and a ReplicaSet verification check.
  Fixed PHP-1104: New Replica Set connections hang when secondaries are creating indexes during initialSync