Regular string that matches RE_SYNSET throws AttributeError

[tylerjharden]

I encountered this while processing sentiment using TextBlob of some live data scraped from the internet. The string field in question was of the value "c-17", which the PatternAnalyzer logic is expecting to be an instance of a Synset, complete with synonyms.

This is incorrect behavior, as it is attempting to access "synonyms" on an instance of an actual string. I have fixed this and will open a pull request.