disk: don't remove trailing slash if path is a single character
disk: don't remove trailing slash if path is a single character

peder2tm/i3status-netdev,ixjlyons/i3status,i3/i3status,peder2tm/i3status-netdev,ixjlyons/i3status,Dettorer/i3status,i3/i3status,lexszero/i3status,Gravemind/i3status,i3/i3status,peder2tm/i3status-netdev,lexszero/i3status,flammi/i3status,jasperla/i3status,jasperla/i3status,ixjlyons/i3status,lexszero/i3status,Dettorer/i3status,lexszero/i3status,flammi/i3status,Dettorer/i3status,jasperla/i3status,Dettorer/i3status,Gravemind/i3status,jasperla/i3status,flammi/i3status,i3/i3status,Gravemind/i3status,ixjlyons/i3status,flammi/i3status,Gravemind/i3status,peder2tm/i3status-netdev