[travis] maybe updating pytest causes mpi snafu?

.travis.yml

@@ -16,7 +16,6 @@ before_install:
  - sudo apt-get install -y -qq python2.7 python-pytest python-docopt python-pytest python-opengl python-distribute ipython python-pyside python-mpi4py
  - sudo apt-get install -y -qq python3-tk cython3 python3-pip python3.4-venv python3-docopt python3-pytest python3-opengl ipython3 python3-pyside python3-mpi4py
  - for pkg in 3to2 https://bitbucket.org/pauloh/pyevtk/get/tip.tar.gz ipyparallel pytest-cov sympy python-coveralls ; do sudo -E ${PIP_X} install ${pkg} ; done
- - sudo -E ${PIP_X} install -U pytest
  # our exp. py3 packages are incompat. with the official repo
  # using aptitude here because it auto-fixes problems
  - |