[fix] Fallback in case of missing HOME variable
[fix] Fallback in case of missing HOME variable

NiLuJe/koreader,koreader/koreader,NiLuJe/koreader,mwoz123/koreader,Frenzie/koreader,poire-z/koreader,Hzj-jie/koreader,Frenzie/koreader,pazos/koreader,mihailim/koreader,Markismus/koreader,koreader/koreader,poire-z/koreader