erp5: remove `erp5-util-develop` part

it's not effective because some zc.recipe.eggs depending on erp5.util
are executed first, so erp5.util is downloaded from pypi.

stack/erp5/buildout.cfg

@@ -70,7 +70,6 @@ extends =
 # keep neoppod extends last
 
 parts +=
-  erp5-util-develop
   slapos-cookbook
   rdiff-backup
   aspell
@@ -601,11 +600,6 @@ entry-points =
   zodbanalyze=erp5.util.zodbanalyze:main
 scripts = zodbanalyze
 
-# develop erp5.util from parts/erp5/
-[erp5-util-develop]
-recipe = zc.recipe.egg:develop
-setup = ${erp5:location}
-
 [cloudooo-repository]
 branch =
 revision = 00604a3a5a69082f7c607665cc6badd5104a32b9