fix comment typo in BUILD.gn

BUG=none
R=andrew@webrtc.org

Review URL: https://codereview.webrtc.org/1370143004 .

Patch from Andrew Bonventre <andybons@chromium.org>.
1 file changed
tree: 60b7b463e727c0f34daaafd9ba572a190a3fc5bb
  1. LICENSE
  2. OWNERS
  3. README.chromium
  4. codereview.settings
  5. dl/