Fix SKIPIFs
Fixed PHP-736: MongoClient connection fails if RP tags match nothing

Also fixed it in all other cases, the MongoClient now never actually
throws a MongoConnection exception as in all cases we have a chance of
being able to fullfill the connection requirements (auth, RP, latency,
whatever) on subsequent requests/or userland changes
(->setReadPreferences(), ->selectDB("db2"), ...)
PHP-736 Test MongoClient construction with tag sets
Make sure the insert is on the secondary we are reading, and clean the

data so it won't be there next time we run the test :)
Fixed PHP-736: MongoClient connection fails if RP tags match nothing