Removing wrong option.

We should not use develop at that level. Because that should not be
published like that, if you want to use the option develop, it may be
used on the highest level of buildout.cfg file.

component/slapos/buildout.cfg

 [buildout]
-# path to slapos.libnetworkcache branch signature
-# git clone https://git.erp5.org/repos/slapos.libnetworkcache.git
-# cd slapos.libnetworkcache && git checkout signature
-#develop = ....slapos.libnetworkcache-signature
 extends =
   ../../stack/shacache-client.cfg
   ../lxml-python/buildout.cfg