textproc/py-textfsm: Update to 1.1.1

This update resolves a package installation conflict with
textproc/py-texttable as both ports installs "texttable.py" into the same
place. [1]

Also while I'm here:

• Switch to GitHub for a while as no sdist tarballs are available at PyPi.

• Make the port concurrent safe because it installs scripts outside of the site-lib directory.

• Remove the "testdata" directory to prevent possible package conflicts as it's only required for the test suite.

• Add a "do-test" target to make future QA easier.

Changelog:

https://github.com/google/textfsm/releases/tag/v1.1.0
https://github.com/google/textfsm/releases/tag/v1.1.1

PR: 244257
Reported by: John Hein <jcfyecrayz@liamekaens.com> [1]
MFH: 2020Q1