Upgrade Aurora to psutil 2.1.1

Testing Done:
Linux and OS X pants test suite.

Bugs closed: AURORA-412

Reviewed at https://reviews.apache.org/r/25466/
Add a test that fails without transactions.
Do MemStorage writes under transactions.
Place transations in consistentReads as well.
Add transactions to weaklyConsistentReads.
Fix indent.
Remove useless code..
Bill's feedback.