The "Extract any text based subtitle streams to *.srt files." plugin is using a static list attribute

[Josh5]

This needs to be modified now that we are not reloading the plugin before each execution.

Eg.

class PluginStreamMapper(StreamMapper):
    sub_streams = []

    def __init__(self):
        super(PluginStreamMapper, self).__init__(logger, ['subtitle'])

to

class PluginStreamMapper(StreamMapper):

    def __init__(self):
        super(PluginStreamMapper, self).__init__(logger, ['subtitle'])
        self.sub_streams = []