Fixed Undefined variable user in $backto if checked out to a non-user
Fixed Undefined variable user in $backto if checked out to a non-user

Fixes [ch9194]

dmeltzer/snipe-it,uberbrady/snipe-it,dmeltzer/snipe-it,uberbrady/snipe-it,ppavlov28/snipe-it,mtucker6784/snipe-it,snipe/snipe-it,uberbrady/snipe-it,uberbrady/snipe-it,snipe/snipe-it,mtucker6784/snipe-it,snipe/snipe-it,mtucker6784/snipe-it,snipe/snipe-it,ppavlov28/snipe-it,dmeltzer/snipe-it,mtucker6784/snipe-it,uberbrady/snipe-it,ppavlov28/snipe-it,dmeltzer/snipe-it,mtucker6784/snipe-it