[fix] DataStorage: create data/dict to prevent Android crash
[fix] DataStorage: create data/dict to prevent Android crash

```
08-12 14:32:17.325  9188  9216 E luajit-launcher: Failed to run script: frontend/util.lua:291: cannot open /storage/emulated/0/koreader/data/dict: No such file or directory
08-12 14:32:17.333  9188  9216 V threaded_app: android_app_destroy!
```
Frenzie/koreader,poire-z/koreader,Markismus/koreader,NiLuJe/koreader,pazos/koreader,mihailim/koreader,mwoz123/koreader,Hzj-jie/koreader,koreader/koreader,lgeek/koreader,Frenzie/koreader,houqp/koreader,NiLuJe/koreader,poire-z/koreader,apletnev/koreader,koreader/koreader