Remove local develop directives.

Those should not be pushed in public repositories, and should be kept as
local changes/commits on developer machine.

software/agent/software.cfg

 [buildout]
-
-develop =
-  /opt/slapdev
-  /opt/slapos.toolbox
-
 extends =
   ../../component/dcron/buildout.cfg
   ../../component/python-2.7/buildout.cfg