Going to add a comment later, but the code that did this same thing was below on lines 28-39. Basically in the attributes file there are attrs that use other attrs, sometimes those are set in roles or on nodes themselves, and in Chef < 11 those attrs can load in an incorrect order and some attributes would not have the correct content because the attr they rely on was set after it was. This line just reloads the attributes to ensure they are set properly.