Simplify conditional in SeoTag::Drop#date_modified (#343)
Simplify conditional in SeoTag::Drop#date_modified (#343)

Merge pull request 343
jekyll/jekyll-seo-tag,jekyll/jekyll-seo-tag,benbalter/jekyll-seo-tag,benbalter/jekyll-seo-tag,benbalter/jekyll-seo-tag,jekyll/jekyll-seo-tag