fix test case TransactionTest

- after thread A inserts a document, there should be 1 (not 0) document
  in the database
- after thread B inserts a document, there should be 2 (not 1) documents
  in the database
add stronger TransactionTestService assertions

- rely on database size and values in database for acceptance criteria as
  opposed to just database size
add test case

for OrientDbTemplate - simple passthrough is sufficient