Lower timeout to 8 hours

erp5testnode hardcoded timeout is 10 hours, and exceeding it results
with no-information.

software/cdn-test/software.cfg

@@ -48,7 +48,7 @@ download-only = true
 on-update = true
 # configuration
 waittime = 3600
-tries = 10
+tries = 8
 
 [template-cdn-test]
 recipe = slapos.recipe.template