buffet: Fix environment variable issue

BUG=b:115406076
TEST=stop buffet; start gale_device_config; see correct
BUFFET_CONFIG_PATH.

Change-Id: Ibed4f530b91544e871f90ae9e073f66a8908cf12
Reviewed-on: https://chromium-review.googlesource.com/1232933
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Mingtian Yin <mtyin@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
(cherry picked from commit 2226baef5db9230385df4f782413924436a20251)
Reviewed-on: https://chromium-review.googlesource.com/1234744
Reviewed-by: Mingtian Yin <mtyin@chromium.org>
Reviewed-by: Srinivasa duvvuri <sduvvuri@google.com>
Commit-Queue: Mingtian Yin <mtyin@chromium.org>
diff --git a/buffet/etc/init/buffet.conf b/buffet/etc/init/buffet.conf
index 534ced2..e708646 100644
--- a/buffet/etc/init/buffet.conf
+++ b/buffet/etc/init/buffet.conf
@@ -5,6 +5,10 @@
 description     "Brillo Buffet Service"
 author          "chromium-os-dev@chromium.org"
 
+# Jetstream devices use BUFFET_CONFIG_PATH to load model id for
+# different boards.
+import BUFFET_CONFIG_PATH
+
 start on starting system-services
 stop on stopping system-services
 respawn