liveusb: reset list of PCI devices assigned to sys-net before assigning new ones

Just in case of installation with persistent configuration.

live/livesys

@@ -102,6 +102,7 @@ if ! strstr "`cat /proc/cmdline`" nopersistenthome && [ -n "$homedev" ] ; then
   action "Mounting persistent /home" mountPersistentHome
 fi
 
+/usr/bin/qvm-prefs --offline-mode -s sys-net pcidevs '[]'
 for dev in $(/sbin/lspci -mm -n | sed -ne 's/^\([0-9][0-9]:[0-9][0-9].[0-9]\) "02.*/\1/p'); do
     /usr/bin/qvm-pci --offline-mode -a sys-net $dev
 done