channeldb: Fix dropped error in migrations test

channeldb: Fix dropped error and wrap with context

channeldb: Fix empty error condition in waitingproof test

channeldb: Fix empty error condition in codec

channeldb: Wrap error in context

channeldb/codec.go

@@ -76,6 +76,7 @@ func WriteElement(w io.Writer, element interface{}) error {
 
 		if e.PubKey != nil {
 			if err := binary.Write(w, byteOrder, true); err != nil {
+				return fmt.Errorf("error writing serialized element: %s", err)
 			}
 
 			return WriteElement(w, e.PubKey)