Fixed PHP-1111: MongoClient constructor crashes on connection to slave.

https://jira.mongodb.org/browse/PHP-1111
You indeed do not need a "slaveOkay" for slave reads, not on the shell either:

{code}
derick@whisky:~ $ mongo localhost:30401
MongoDB shell version: 2.6.0
connecting to: localhost:30401/test
> db.isMaster()['ismaster'];
false
> db['master-slave/bug01111'].find();
{ "_id" : ObjectId("5395ca6844670a99598b4568"), "test" : NumberLong(42) }
{code}

Variable names are now updated.