futility/updater: update smm store filename to use an underscore

Rename "smm store" to "smm_store".

Depends on CL:1351857.

BUG=b:120060878
TEST=None

Change-Id: Iae511ecdc6d918d06218de1b651b1e5e3821d2f1
Reviewed-on: https://chromium-review.googlesource.com/1351178
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
1 file changed