Enable F40X checking

Clean up imports due to F401 and F403 checks.
F401  'module' imported but unused
F403  unable to detect undefined names with wildcard import

Change-Id: I487edb157de1a6babc7ad8a3fb65f195e476c490
Remove unused package in requirement.txt

This patch is similar to https://bugs.launchpad.net/glance/+bug/1252344.

Currently wsgiref/passlib package exist in requirement.txt,
but I confirmed that they are unused in glance source by "grep" command.

I removed them to clean up.

Closes-bug: #1255826
Change-Id: Ibbc2f1d413efacd0c18ba16c9250ef08470667d1
Use assertEqual instead of assertEquals in unit tests

The method assertEquals has been deprecated since python 2.7.
http://docs.python.org/2/library/unittest.html#deprecated-aliases
Also in Python 3, a deprecated warning is raised when using assertEquals
therefore we should use assertEqual instead.

Change-Id: Ic8f152766d70146300b74f3803d7dab1e4de50e2
Closes-Bug: #1256734
Replace deprecated method assertEquals

TestCase.assertEquals is deprecated since Python 2.7, so need use new
method name assertEqual.
See http://docs.python.org/2/library/unittest.html#deprecated-aliases

Change-Id: Iae9074f2afe2a572b60f6192aa6c871db42360ec
DB migration changes to support DB2 as sqlalchemy backend

Implements bp db2-database

SQLAlchemy works in general, only changes needed to allow DB2
backend are these migration updates. The main difference
with DB2 is around index creation and constraints updates.

Change-Id: If5aa371328ef49ec93029ed15993871cfe5522cd
Merge "Enable F40X checking"
Merge "Replace deprecated method assertEquals"
Merge "Use assertEqual instead of assertEquals in unit tests"
Merge "DB migration changes to support DB2 as sqlalchemy backend"
Merge "Remove unused package in requirement.txt"