Change OWNERS of whitespace file to *.

BUG=

Review-Url: https://codereview.chromium.org/2662573003
Cr-Original-Commit-Position: refs/heads/master@{#446846}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 01dc7f2e227a07cc4b867769437a8e51cb0a538e

OWNERS

@@ -10,3 +10,4 @@ per-file mac_toolchain.py=erikchen@chromium.org
 per-file mac_toolchain.py=justincohen@chromium.org
 per-file package_mac_toolchain.py=erikchen@chromium.org
 per-file package_mac_toolchain.py=justincohen@chromium.org
+per-file whitespace_file.txt=*