Revert "Switch to slapos.buildout development too."

This reverts commit a40f1c1f.

dev.py

@@ -140,7 +140,7 @@ if not os.path.exists(partsdir):
     os.mkdir(partsdir)
 zc.buildout.easy_install.sitepackage_safe_scripts(
     'bin', pkg_resources.working_set, sys.executable, partsdir,
-    reqs=['slapos.buildout'])
+    reqs=['zc.buildout'])
 
 bin_buildout = os.path.join('bin', 'buildout')