use isinstance(X, Y) instead of 'type(X) is Y'
rm unused vars reported by pyflakes
avoid extra .strip() in version.py
not X == Y  ->  X != Y
Merge pull request #4730 from hulu/isinstance-not-type-is

use isinstance(X, Y) instead of 'type(X) is Y'
Merge pull request #4731 from hulu/rm-unused-vars-pyflakes

remove some unused vars reported by pyflakes
Merge pull request #4732 from hulu/pre-strip-git-version

avoid extra .strip() in version.py via trivial refactor
Merge pull request #4733 from hulu/use-ne-operator

not X == Y  ->  X != Y