MGO-161 Add modern server versions to test suite

[ShaneHarvey]

TODO:

• Fixed: On 4.0, lots of tests fail with:

  session_test.go:4129:
      c.Assert(iter.Err(), ErrorMatches, "unauthorized.*|not authorized.*")
  ... error string = "command find requires authentication"
  ... regex string = "unauthorized.*|not authorized.*"
  

• On 3.4, TestCollationQueries fails with:

  c.Assert(err, IsNil)
  ... value *mgo.QueryError = &mgo.QueryError{Code:67, Message:"Invalid index specification { name: \"text_number_1\", ns: \"mydb.mycoll\", key: { text_number: 1 }, collation: { locale: \"en\", numericOrdering: true } }; cannot create an index with the 'collation' option and v=1", Assertion:false} ("Invalid index specification { name: \"text_number_1\", ns: \"mydb.mycoll\", key: { text_number: 1 }, collation: { locale: \"en\", numericOrdering: true } }; cannot create an index with the 'collation' option and v=1")
  

• On 4.0, TestModeMonotonicWriteOnIteration sometimes fails with:

  [LOG] 0.14717 Socket 0xc8204a8b60 to localhost:40012: received document: bson.M{"cursor":bson.M{"firstBatch":[]interface {}{bson.M{"_id":"[\xe4\xae\xc0@\xc5Lq\x89$\xdf^", "n":40}}, "id":0, "ns":"mydb.mycoll1"}, "ok":1, "operationTime":6621609491798425602, "$gleStats":bson.M{"lastOpTime":0, "electionId":"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"}, "lastCommittedOpTime":6621609491798425601, "$configServerState":bson.M{"opTime":bson.M{"t":1, "ts":6621609466028621827}}, "$clusterTime":bson.M{"clusterTime":6621609491798425608, "signature":bson.M{"hash":[]uint8{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, "keyId":0}}}
  [LOG] 0.14731 Iter 0xc8200c1a40 received reply document 1/1 (cursor=0)
  [LOG] 0.14736 Iter 0xc8200c1a40 document unmarshaled: &mgo_test.M{"_id":"[\xe4\xae\xc0@\xc5Lq\x89$\xdf^", "n":40}
  [LOG] 0.14737 Iter 0xc8200c1a40 exhausted with cursor=0
  cluster_test.go:355:
      c.Assert(i, Equals, len(ns))
  ... obtained int = 1
  ... expected int = 7
  

  See https://travis-ci.org/10gen/mgo/jobs/452602673#L1288.

[xdg]

The commit is fine except for the failures. IIRC 4.0 required auth for a lot of things that didn't used to require it.

[ShaneHarvey]

There's another problem here that needs to be addressed. The test set up often fails with "not master" when attempting to insert or create users in what the test suite believes is the primary node. I believe this is because in more recent server versions the node that runs replSetInitiate does not always become the primary. We're facing a similar issue in https://jira.mongodb.org/browse/PYTHON-1644.

[ShaneHarvey]

I don't have time to complete this PR so I'm going to close it.