erp5-bin: Not inherit the section from erp5

This is a workaround, erp5testnode seems will change the
erp5:revision dynamically and it will infect the erp5-bin
which inherit from erp5. Remove this inhertige to avoid
this influence.

stack/erp5/buildout.cfg

@@ -344,9 +344,10 @@ link-binary =
 <= download-base
 
 [erp5-bin]
-<= erp5
+recipe = slapos.recipe.build:gitclone
 repository = https://lab.nexedi.com/nexedi/erp5-bin.git
 branch = master
+git-executable = ${git:location}/bin/git
 
 [bt5-repository]
 # Format: