Update fallback value of BASE_VER from 180609 to 242728.

CL:185235 already updated gobi-cromo-plugin to build against
libchrome-242728. This CL just updates the fallback value of BASE_VER in
Makefile to 242728.

TEST=Tested the following:
1. `FEATURES=test emerge-$BOARD gobi-cromo-plugin`
2. Verify that cromo can load the gobi and madison plugin.
3. Run network_3GSmokeTest with a Gobi3k modem.

Change-Id: I9db80882c73c4270110176b82712c85eb5b21350
Reviewed-on: https://chromium-review.googlesource.com/194524
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed