Fix duplicated WOFF mime-type

A copy-paste error meant that the WOFF mime-type was duplicated and the
WOFF2 mime-type never defined.

Spotted by Alex Henrie <alexhenrie24@gmail.com>
1 job for master in 3 minutes and 1 second (queued for 11 minutes and 9 seconds)
Status Job ID Name Coverage
  Test
passed #277185
build

00:03:01