Fix eth loading in xsession for #polybar

i3/.xsession

@@ -1,2 +1,3 @@
 WLAN=/sbin/ifconfig | grep wlp | tail -1 | cut -d ':' -f 1
+ETH=/sbin/ifconfig | grep veth | tail -1 | cut -d ':' -f 1
 i3

polybar/.config/polybar/config

@@ -85,7 +85,6 @@ label = %title:0:30:...%
 type = internal/xkeyboard
 blacklist-0 = num lock
 
-format-prefix = " "
 format-prefix-foreground = ${colors.foreground-alt}
 format-prefix-underline = ${colors.secondary}
 
@@ -242,11 +241,10 @@ ramp-signal-foreground = ${colors.foreground-alt}
 
 [module/eth]
 type = internal/network
-interface = vethf838df41
+interface = ${env:ETH:vethf838df41}
 interval = 3.0
 
 format-connected-underline = #55aa55
-format-connected-prefix = " "
 format-connected-prefix-foreground = ${colors.foreground-alt}
 label-connected = %local_ip%