Pinned version of pytest-cov to <2.6
Pinned version of pytest-cov to <2.6

Details:

* pytest-cov 2.6.0 has increased its version requirement for the
  coverage package from coverage>=3.7.1 to coverage>=4.4. That is
  in conflict with the version requirement of python-coveralls
  for coverage==4.0.3.

  As a workaround, this change pins the version of pytest-cov to <2.6.
  An issue against pytest-cov has been opened:
  https://github.com/z4r/python-coveralls/issues/66

  Once that issue is resolved, the workaround can be removed again,
  probably 2.6.0 needs to continue to be excluded.

Signed-off-by: Andreas Maier <38dbb04957d222ea6ce72de72413b1e55e665472@de.ibm.com>

zhmcclient/python-zhmcclient,zhmcclient/python-zhmcclient