Remove emptytimebuf from print_battery_info.
Remove emptytimebuf from print_battery_info.

This changes the behavior for NetBSD: previously this time was not
shown while charging. On Linux it was treated as "full time". This
change makes all OSes behave the same.

OpenBSD and FreeBSD did not support emptytime previously.

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