devel/py-pytest: Update to 2.8.7

• Update PORTVERSION and distinfo checksum (2.8.7)
• Remove nose from TEST_DEPENDS (only mentioned in tox.ini)
• Patch setup.py not to install version-suffixed console_scripts
• Enable "concurrent" Python installation accordingly
• Remove USES=zip, DISTFILES is now a tarball

Changes:

http://pytest.org/latest/changelog.html