Fix duplicate parameter key concatenation in smart filter

[osxtest]

https://github.com/Qianlitp/crawlergo/blob/c47db8c53730d4db1b7a5ef6b622a97eb4e9ff37/pkg/filter/smart_filter.go#L285-L287

Based on above code, I think the name for filterLocationSet should be one key at a time, instead of concatenating them all together.