Handle smallfile version control from github release instead of tag

[dustinblack]

Please describe what you would like to see in this project

Smallfile currently uses a tag to clone a release, but tags can move. This could be problematic, so change the method to pull the release tarball instead.

[portante]

See also distributed-system-analysis/smallfile#34

[portante]

Or consider using RPMs, PyPI, etc.

[dustinblack]

For now it looks like we have to stick with the release tag for smallfile until either a 1.1 release build is done or distributed-system-analysis/smallfile#34 is addressed and smallfile 1.1 is available via PyPi. The latest release build is v1.0.1 which does not include the needed histogram features.

[portante]

I just released smallfile using the 1.1 tag, see https://github.com/distributed-system-analysis/smallfile/releases/tag/1.1.