[LNT] Python 3 support: fix report version literal

[thopre]

Summary

The upgrade_1_to_2 module stores a report_version string literal in
the Parameter column of the Run table which is declared as binary data.
This does not work in Python 3 where strings/text and binary are
different things. This commit changes it for a binary literal instead
(introduced in Python 2.6).

[thopre]

Ping?

[hubert.reinterpretcast]

LGTM.

lnt/server/db/migrations/upgrade_1_to_2.py

def update_testsuite(engine, session, db_key_name):
     sqlalchemy.orm.mapper(Order, order_table)
     sqlalchemy.orm.mapper(Run, run_table)
 
     # Scan each run that has no report version and possibly recompute the
     # run order.
     logger.info("updating runs")
     all_runs = session.query(Run).\
         filter(sqlalchemy.not_(Run.Parameters.like(
-                '%["__report_version__"%'))).all()
+                b'%["__report_version__"%'))).all()
     for i, run in enumerate(all_runs):
         if i % 1000 == 999:
             logger.info("update run %d of %d" % (i + 1, len(all_runs)))
 
         # Extract the parameters.
         run_info = dict(json.loads(run.Parameters))
 
         # Sanity check this was an inferred run order.