Fix uncaught exceptions when unpickling plugins file

            except EnvironmentError as exc:

                logger.error('Cannot load previous plugins: %s (%s)',

                             exc.errno, exc.strerror)

            except pickle.UnpicklingError as exc:

            except (

                EOFError,

                AttributeError,

                ImportError,

                IndexError,

                pickle.UnpicklingError,

            ) as exc:

                logger.error('Cannot read file, bad format, %s', exc)

            else:

                def plugins_install():