Don't pass kwargs to connection.execute()

Resolve the following RemovedIn20Warning warning:

  The connection.execute() method in SQLAlchemy 2.0 will accept
  parameters as a single dictionary or a single sequence of dictionaries
  only. Parameters passed as keyword arguments, tuples or positionally
  oriented dictionaries and/or tuples will no longer be accepted.

Change-Id: I44675fce86337696b6494abc03e8058af32686c6
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>