[api] improve error message

src/api/app/models/channel.rb

@@ -125,7 +125,7 @@ def update_from_xml(xmlhash)
         p=b
       end
       # no match? either not created or searched in the right way
-      raise "Unable to find binary list" unless p
+      raise "Unable to find binary list #{cbl.project.name} #{cbl.repository.name} #{cbl.architecture.name}" unless p
       # update...
       _update_from_xml_binaries(cbl, p)
     }