Add cleanup script when update.
Add cleanup script when update.

Clear translation cache in localStorage when updating to 1.2
The cleanup script will be removed in next release.

wangjun/crx-transit,wangjun/crx-transit,Chen0719/crx-transit,GDG-Xian/crx-transit,Chen0719/crx-transit,Chen0719/crx-transit,GDG-Xian/crx-transit,wangjun/crx-transit