76352bda80
Update all .py source files by
$ pyupgrade --py3-only $(git ls-files | grep ".py$")
to modernize the code according to Python 3 syntaxes.
pep8 errors are fixed by
$ autopep8 --select=E127,E128,E501 --max-line-length 79 -r \
--in-place oslo_db
Also add the pyupgrade hook to pre-commit to avoid merging additional
Python 2 syntaxes.
Change-Id: Ia3a9b33edccde7b083188db30e9766470b10dbab