Trying again, this time change 'alltests.cfg' also.

Simplified buildout configurations by removing references to '${buildout:eggs}'.
They are not needed because there is only one egg (Zope2) required for each part

alltests.cfg

@@ -8,7 +8,7 @@ parts += alltests
 [alltests]
 recipe = zc.recipe.testrunner
 eggs =
-    ${buildout:eggs}
+    Zope2
     Acquisition
     DateTime
     ExtensionClass

buildout.cfg

@@ -9,12 +9,10 @@ parts =
 extends = versions-zope2.cfg
 versions = versions
 unzip = true
-eggs =
-    Zope2
 
 [test]
 recipe = zc.recipe.testrunner
-eggs = ${buildout:eggs}
+eggs = Zope2
 
 [scripts]
 recipe = zc.recipe.egg:scripts
@@ -22,6 +20,6 @@ eggs = Zope2
 
 [zopepy]
 recipe = zc.recipe.egg
-eggs = ${buildout:eggs}
+eggs = Zope2
 interpreter = zopepy
 scripts = zopepy