kobo: detect non-epoch timestamp using current second
kobo: detect non-epoch timestamp using current second

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