New slapos.libnetworkcache requires M2Crypto.

component/slapos/buildout.cfg

 [buildout]
 extends =
   ../../stack/shacache-client.cfg
+  ../m2crypto/buildout.cfg
   ../lxml-python/buildout.cfg
   ../python-2.7/buildout.cfg
 
@@ -29,10 +30,14 @@ allowed-eggs-from-site-packages =
 [lxml-python]
 python = python2.7
 
+[M2Crypto]
+python = python2.7
+
 [slapos]
 recipe = z3c.recipe.scripts
 python = python2.7
 eggs =
+  ${M2Crypto:egg}
   slapos.libnetworkcache
   zc.buildout
   ${lxml-python:egg}