dev-install: fix OWNERS path

The find owners module will use the path in the current repo as the
implicit prefix even when crossing repo boundaries, so make sure we
have an explicit / anchor when loading from chromite.

BUG=None
TEST=find owners can find owners for this

Change-Id: I10037746f3b0f8a935f0f69e43d9475a7c3b665f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2332368
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Stephane Belmon <sbelmon@google.com>
Commit-Queue: Stephane Belmon <sbelmon@google.com>
diff --git a/dev-install/OWNERS b/dev-install/OWNERS
index 5d3a805..592f350 100644
--- a/dev-install/OWNERS
+++ b/dev-install/OWNERS
@@ -1,3 +1,3 @@
-include chromiumos/chromite:OWNERS.build
+include chromiumos/chromite:/OWNERS.build
 
 # COMPONENT: Infra>ChromeOS>Build>Platform