keep only one instance of reader.lua
keep only one instance of reader.lua

in case the reader crashed without cleaning up the forked subprocess lipc-wait-event
chihyang/koreader,NickSavage/koreader,houqp/koreader,robert00s/koreader,chrox/koreader,lgeek/koreader,NiLuJe/koreader,Frenzie/koreader,koreader/koreader,noname007/koreader,mwoz123/koreader,Hzj-jie/koreader,Markismus/koreader,apletnev/koreader,Frenzie/koreader,frankyifei/koreader,NiLuJe/koreader,pazos/koreader,ashhher3/koreader,mihailim/koreader,poire-z/koreader,poire-z/koreader,koreader/koreader,ashang/koreader