Replace zea@ as owner of sync

The new team now takes ownership of a few remaining directories.

Removing zea@ and pavely@ as owners from components/sync, after we've
been acting as owners for a while.

Bug: None
Change-Id: Ida9c8e7b22d40f16813aea0f521ab20ad170b49e
Reviewed-on: https://chromium-review.googlesource.com/1103572Reviewed-by: Nicolas Zea <zea@chromium.org>
Commit-Queue: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568036}

chrome/android/java/src/org/chromium/chrome/browser/sync/OWNERS

+mastiz@chromium.org
 nyquist@chromium.org
 yfriedman@chromium.org
-zea@chromium.org
 
 # COMPONENT: Services>Sync

chrome/android/javatests/src/org/chromium/chrome/browser/sync/OWNERS

+mastiz@chromium.org
 nyquist@chromium.org
 yfriedman@chromium.org
-zea@chromium.org
 
 # COMPONENT: Services>Sync

chrome/android/sync_shell/OWNERS

+mastiz@chromium.org
 nyquist@chromium.org
 yfriedman@chromium.org
-zea@chromium.org
 
 # COMPONENT: Services>Sync

chrome/test/android/javatests/src/org/chromium/chrome/test/util/browser/sync/OWNERS

+mastiz@chromium.org
 nyquist@chromium.org
 yfriedman@chromium.org
-zea@chromium.org
 
 # COMPONENT: Services>Sync

components/sync/OWNERS

 mastiz@chromium.org
-pavely@chromium.org
 treib@chromium.org
-zea@chromium.org
+tschumann@chromium.org
 
 # COMPONENT: Services>Sync