Remove jar@ from some OWNERS

(since he's no longer doing reviews)

Bug: 
Change-Id: I0ff731864705a88006b159f26781856402cd737e
Reviewed-on: https://chromium-review.googlesource.com/825002Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: Julia Tuttle <juliatuttle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523802}

chrome/renderer/net/OWNERS

-jar@chromium.org
 mmenke@chromium.org
 juliatuttle@chromium.org
 

components/neterror/OWNERS

-jar@chromium.org
 mmenke@chromium.org
 juliatuttle@chromium.org
 edwardjung@chromium.org

components/network_hints/OWNERS

-jar@chromium.org
 juliatuttle@chromium.org