Please review: Issue 7 - Add pause and resume methods to topology fixtures

[Simon Pichugin]

Hi team,
for replication test suite I need a tool that can stop the replication
on a big amount of agreements (4 and more, for instance).
Please, review the patch:

https://pagure.io/lib389/issue/7
https://pagure.io/lib389/issue/raw/files/b60a5748102ee2a48a8d3b79d6e0b8d5509...

Thanks,
Simon