fix tests - webapp test should only depend on soledad if soledad service is present

tests/server-tests/white-box/webapp.rb

@@ -4,7 +4,7 @@ require 'json'
 
 class Webapp < LeapTest
   depends_on "Network"
-  depends_on "Soledad"
+  depends_on "Soledad" if service?(:soledad)
 
   def setup
   end