gitlab: use slapos-cookbook-develop + pin slapos cookbook version

This is needed until the patch regarding `pidfile` in wrapper.py
is added to SlapOS cookbook.

software/gitlab/software.cfg

@@ -40,6 +40,8 @@ parts =
 #   for instance
     instance.cfg
 
+    slapos-cookbook-develop
+
     slapos-cookbook
     eggs
 
@@ -50,6 +52,10 @@ parts =
     dcron-output
     logrotate
 
+[slapos.cookbook-repository]
+repository = https://lab.nexedi.com/nexedi/slapos.git
+revision = 571d6514f7290e8faa9439c4b86aa2f6c87df261
+
 
 ############################
 #   Software compilation   #