Wait for minio to start with greater precision

[sjperkins]

• [x] Tests added / passed

  $ py.test -v -s daskms/tests

  If the pep8 tests fail, the quickest way to correct this is to run autopep8 and then flake8 and pycodestyle to fix the remaining issues.

  $ pip install -U autopep8 flake8 pycodestyle
  $ autopep8 -r -i daskms
  $ flake8 daskms
  $ pycodestyle daskms

• [x] Fully documented, including HISTORY.rst for all changes and one of the docs/*-api.rst files for new API

  To build the docs locally:

  pip install -r requirements.readthedocs.txt
  cd docs
  READTHEDOCS=True make html

[sjperkins]

Wait until Documentation: is output by the process as the criterion for considering the minio server started.

Automatically configured API requests per node based on available memory on the system: 11357
Finished loading IAM sub-system (took 0.0s of 0.0s to load data).
Status:         1 Online, 0 Offline.
API: http://146.231.135.142:9000  http://146.231.131.94:9000  http://10.0.1.1:9000  http://10.88.0.1:9000  http://172.17.0.1:9000  http://10.1.217.0:9000  http://127.0.0.1:9000
RootUser: minioadmin
RootPass: minioadmin

Console: http://146.231.135.142:42181 http://146.231.131.94:42181 http://10.0.1.1:42181 http://10.88.0.1:42181 http://172.17.0.1:42181 http://10.1.217.0:42181 http://127.0.0.1:42181
RootUser: minioadmin
RootPass: minioadmin

Command-line: https://docs.min.io/docs/minio-client-quickstart-guide
   $ mc alias set myminio http://146.231.135.142:9000 minioadmin minioadmin

Documentation: https://docs.min.io