gs_archive_server: add nebraska to path

Add nebraska dir, and consequently nebraska.py, to path in
gs)_archive_server executable. This is necessary for the fake omaha
implemetation.

BUG=chromium:1078188
TEST=None

Change-Id: I19294bca1ada91f5aadcf64b2b569c7f6f72f583
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2274928
Tested-by: Sanika Kulkarni <sanikak@chromium.org>
Commit-Queue: Sanika Kulkarni <sanikak@chromium.org>
Auto-Submit: Sanika Kulkarni <sanikak@chromium.org>
Reviewed-by: Congbin Guo <guocb@chromium.org>
diff --git a/bin/gs_archive_server b/bin/gs_archive_server
index a0b5e56..2cc73a1 100755
--- a/bin/gs_archive_server
+++ b/bin/gs_archive_server
@@ -6,7 +6,8 @@
 # Run Google Storage archive server from inside virtual environment.
 set -eu
 readonly bindir=$(dirname -- "$(readlink -e -- "$0")")
-readonly homedir=$(cd "$bindir"/../gs_cache; pwd)
-export PYTHONPATH=$homedir
+readonly homedir=$(cd "${bindir}"/../gs_cache; pwd)
+readonly nebraska_dir=$(cd "${bindir}"/../nebraska; pwd)
+export PYTHONPATH=${homedir}:${nebraska_dir}
 
-exec vpython -vpython-spec $homedir/.vpython -m gs_archive_server "$@"
+exec vpython -vpython-spec "${homedir}"/.vpython -m gs_archive_server "$@"