Revert "Added some diagnostic code to TestPing to help figure out why it fails on Jenkins."

This reverts commit ed913d07b35f8b13dd90de6e8f3dca02186b130e.
Revert "Instrument TestPing failure."

This reverts commit 72c33701719dd357f185276f3bed6eaf96b08a9b.
ignoring eval tests when run with authentication.
fixed issue with journalled write concerns on a mongos when the underlying shards have journaling disabled.
changed ScramSha1 random string to be more secure using the RNGCryptoServiceProvider.
exception is different for different versions of the server.
removed threadstatic attribute causing tests to fail randomly.
fixed failing test on 2.7 nightly due to change in explain results.