Remove unnecessary assignment.

Gained 3 bytes.

Obviously, if you've got dead code or -- as in this case -- moot code
removing it decreased minzipped size. This late in a project gains such
as this are hard to find though.

See #46.

File                             Raw         Min         Zip     Min/Zip
index.js                  5655/05.52  2117/02.07  1867/01.82  1013/00.99