Py2to3: Futurize stage 2

[inferno-chromium]

As part of Python 3 migration (#183)

git ls-files "*.py" | xargs futurize -w -n --stage2

obviously not as simple. need to be done in steps, and str and unicode fixes are the more tricky ones.

[inferno-chromium]

Need to think about these

src/local/butler/generate_datastore_models.py:  if py_type == long:
src/python/platforms/android/device.py:  if isinstance(value, long):

[inferno-chromium]

Remaining ones, probably for Q3 and need to do str-unicode ones more carefully.

libfuturize.fixes.fix_unicode_keep_u
libfuturize.fixes.fix_future_standard_library_urllib (maybe start using requests, careful on exception handling)
libfuturize.fixes.fix_future_standard_library
libfuturize.fixes.fix_object
libfuturize.fixes.fix_basestring
libfuturize.fixes.fix_future_builtins

[inferno-chromium]

Remaining (in libfuturize.fixes.fix_object, didn't do ndb_patcher since it is going away):

libfuturize.fixes.fix_unicode_keep_u
libfuturize.fixes.fix_future_standard_library
libfuturize.fixes.fix_basestring
libfuturize.fixes.fix_future_builtins

[oliverchang]

i'll tackle the unicode/str conversion

[inferno-chromium]

For future, need to careful of any migration change in docker/ dir, example breakage due to 6d9f9e7#diff-f1db2c4f1d1b92aef6e74abff3119154 (my bad :() since we don't have future lib during start_host.py time. also got noticed when we updated host image.

[inferno-chromium]

Just for tracking, we include everything now except libfuturize.fixes.fix_unicode_keep_u and libfuturize.fixes.fix_future_builtins (these need more work, will come later). minor exclusion is ndb_patcher which will go away soon.

To replicate / reapply fixes, do
git ls-files "*.py" | xargs futurize -w -n --stage2 -x libfuturize.fixes.fix_unicode_keep_u -x libfuturize.fixes.fix_future_builtins

[oliverchang]

All the futurize fixes were completed.