Check for valid model before attempting to access fieldsets
Check for valid model before attempting to access fieldsets

Fixes [ch1249]

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