Kobo (koreader.sh): install OTA update in working directory
Kobo (koreader.sh): install OTA update in working directory

Thanks to @a-kohout

Fixes #2752

pazos/koreader,Markismus/koreader,robert00s/koreader,poire-z/koreader,mwoz123/koreader,NiLuJe/koreader,poire-z/koreader,lgeek/koreader,Frenzie/koreader,mihailim/koreader,Hzj-jie/koreader,koreader/koreader,houqp/koreader,apletnev/koreader,koreader/koreader,Frenzie/koreader,NiLuJe/koreader