DB: Remove unnecessary subtransactions=True

It is only necessary to pass subtransactions=True to session.begin()
when the new transactions may be called from inside an existing
transaction. There is *no* need to pass it from the top level
transaction in anticipation that there may be subtransactions. The
sqlalchemy docs are not 100% clear on this so we were doing both to be
sure to be sure, but we have confirmed that the latter is not required.

Since passing subtransactions=True when it is not required may cover up
other problems, remove it except in those cases where we know the API
may be called as a subtransaction.

Change-Id: I34cbd3526aef79132f6d97569d48a347e904ab75
Task: 37000

0 files changed, 0 insertions, 0 deletions