Remote service errors are saved into the result file

1) Run the schema which makes the remote request (e.g. _common_data\cmdline\custom\534\remote.uwl).
2) There must be some problems with the remote service (or no internet connection).
Bug state: the html-page with a error is saved into the result file (file.gb). UGENE tries to open it as correct file (genbank).
Resolution: show the errors to a user and do not create result files in that case.