Enhance tests for LOG.deprecated

The tests for LOG.deprecated were incorrect because they were
clearing the log buffers on every call.

When this is corrected, it shows that LOG.deprecated is not working
as expected since it logs multiple times when the test indicates
that it should only log once.

Change-Id: Ic0e4925c372e5948c2140daa07ab3362fb25a306
Partial-Bug: #1266812
Fix deprecated messages sent multiple times

Calling LOG.deprecated('...') multiple times with the same log
message was causing the message to be logged multiple times. The
message should only have been logged once.

Change-Id: Ieab0bf2656761759966cf16f1de05bcb41cd1be5
Closes-Bug: #1266812
py3kcompat: remove

Everything is already in six>=1.4.0 and we already depend on such a
version. There's no reason to keep this file.

Change-Id: I06b90f789ae21f2ef8b8071b4298bfc0406482a6
Implements SI/IEC unit system conversion to bytes

The issues with utils.to_bytes are

1) Ignores measure of unit and treats b and B both as Byte
2) Cannot handle SI unit system which base is 1000 (IEC=1024)
3) The name "to_bytes" didn't do a good job representing what the function does.
   Disscussed here,
       https://review.openstack.org/#/c/32093/2/openstack/common/strutils.py

This patch implements "string_to_bytes". The name comes from
"string_to_bool" in cinder/utils.py. Its merits are,

1) Handles bit and byte units
2) Handles SI and IEC unit systems
3) Has a much more intuitive function name

Closes-bug: #1189635
Closes-bug: #1193765

Change-Id: I5f1ce56f447179d1ef6ded7c956983151f5a8f18
Add etc/openstack.conf.sample to .gitignore

etc/openstack.conf.sample is generated when running the unit tests, so
add it ti .gitignore

Change-Id: Iee41f9f433c3cbe55a832a319564dfb90eec99b7
Merge "Implements SI/IEC unit system conversion to bytes"
Merge "Enhance tests for LOG.deprecated"
Merge "Fix deprecated messages sent multiple times"
Merge "py3kcompat: remove"
Merge "Add etc/openstack.conf.sample to .gitignore"