Add to content/network/OWNERS

This CL modifies content/network/OWNERS file to add one additional owner and
remove an existing one.

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I3bf8464cbfe9026801b7cf30d0076e87084ccc30
Reviewed-on: https://chromium-review.googlesource.com/749525Reviewed-by: Asanka Herath <asanka@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Helen Li <xunjieli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513209}

content/network/OWNERS

 ananta@chromium.org
-asanka@chromium.org
 jam@chromium.org
 kinuko@chromium.org
 mmenke@chromium.org
 rdsmith@chromium.org
 scottmg@chromium.org
+xunjieli@chromium.org
 yhirano@chromium.org
 yzshen@chromium.org