Manually increment revision numbers in revision plugin

Don't rely on the SQLAlchemy revision_col flag to bump revision
numbers and instead bump them in a before_flush handler. This
will allow the follow-up patch to do enforcement on conditional
updates before the revision number is incremented.

Partial-Bug: #1493714
Partially-Implements: blueprint push-notifications
Change-Id: I5feeec5b8385727eff53dc669363bc41db8ceaba
1 file changed
tree: be55b151dae89e55dd081901f650a10cb399735f
  1. neutron/