Add thomasanderson as an OWNER of //src/build/linux

R=dpranke@chromium.org

Review-Url: https://codereview.chromium.org/2712643005
Cr-Original-Commit-Position: refs/heads/master@{#452360}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 3cd4d8506ad29a689491f46e90f177560de9e2d2

linux/OWNERS

@@ -1,3 +1,4 @@
 mmoss@chromium.org
 phajdan.jr@chromium.org
 thestig@chromium.org
+thomasanderson@chromium.org