Add lockfile>=0.8 to requirements.txt

The new oslo version of the oslo db.sqlalchemy module depends on the
lockfile package. This patch will be used by a following patch which
will sync the new db.sqlalchemy module from oslo to Ironic.

Change-Id: I2540c324b4863405681cb8aac90a4b139e931318
Related-Bug: #1272500
Sync db.sqlalchemy code from Oslo

Patch contains common code from Oslo, we need to sync this modules to fix
a problem with a newer version of sqlite and the db.sqlachemy module that
is causing some of tests to fail if the version of the sqlite is >=3.7.16.

The patch also includes the code needed with the transition from migrate
tool to alembic, these base migration classes depends on the py3kcompat
and test modules which were also added to the project.

Closes-Bug: #1272500
Change-Id: Ifcd1254f16506a4247523056d6ad4ad8d7aefdac
Merge "Add lockfile>=0.8 to requirements.txt"
Merge "Sync db.sqlalchemy code from Oslo"