[dev] Turned an error message to a warning

generators/oar-properties/oar-properties.rb

@@ -266,7 +266,7 @@ if options[:diff]
     properties_keys["diff"][k] = v_ref unless v_oar
     if v_oar && v_oar != v_ref && v_ref != NilClass && v_oar != NilClass
       # Detect inconsistency between the type (String/Fixnum) of properties generated by this script and the existing values on the server.
-      raise "Error: the OAR property '#{k}' is a '#{v_oar}' on the server and this script uses '#{v_ref}' for this property."
+      puts "Error: the OAR property '#{k}' is a '#{v_oar}' on the server and this script uses '#{v_ref}' for this property."
     end
   }