[owners] Clean up //build/OWNERS

Remove global owners.
Remove per-file owners for reasons that are now stale IIUC.

Change-Id: Ic26ffaa9f322bda2a0706516f718419f3cc5c628
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/490577
Fuchsia-Auto-Submit: Shai Barack <shayba@google.com>
Reviewed-by: Adam Barth <abarth@google.com>
Reviewed-by: Shai Barack <shayba@google.com>
Commit-Queue: Shai Barack <shayba@google.com>
diff --git a/build/OWNERS b/build/OWNERS
index a324c63..636445a 100644
--- a/build/OWNERS
+++ b/build/OWNERS
@@ -1,16 +1,5 @@
-jamesr@google.com
-mcgrathr@google.com
-phosek@google.com
-pylaligand@google.com
-raggi@google.com
-abarth@google.com
-joshuaseaton@google.com
 digit@google.com
 shayba@google.com
 jayzhuang@google.com
-rudymathu@google.com
 fangism@google.com
-per-file BUILD.gn=bryanhenry@google.com
-per-file BUILD.gn=zarvox@google.com
-per-file BUILD.gn=shayba@google.com
-per-file package.gni=shayba@google.com
+rudymathu@google.com