Switch to 'usedevelop = true' FBO nose / coverage.

tox.ini

@@ -24,14 +24,10 @@ deps =
     zope.testing
 
 [testenv:coverage]
+usedevelop = true
 basepython =
     python2.7
 commands =
-#   The installed version messes up nose's test discovery / coverage reporting
-#   So, we uninstall that from the environment, and then install the editable
-#   version, before running nosetests.
-    pip -q uninstall -y zope.container
-    pip -q install -e .
     nosetests --with-xunit --with-xcoverage
 deps =
     {[testenv]deps}