od: fix infinite loop at EOF
od: fix infinite loop at EOF

Fixes #866

Heather/coreutils,tempbottle/coreutils,ebfe/coreutils,kwantam/coreutils,keunwoo/coreutils,uutils/coreutils,ebfe/coreutils,Heather/coreutils,kwantam/coreutils,uutils/coreutils,tempbottle/coreutils,jbcrail/coreutils,keunwoo/coreutils,Arcterus/coreutils,wimh/coreutils,Arcterus/coreutils,jbcrail/coreutils,kevgeniy/coreutils,wimh/coreutils,kevgeniy/coreutils,uutils/coreutils