Update itempos.pl
Update itempos.pl

 Fix getting long file name string. If the extension verison was not a x03, x07 or x08 the start position was set to null to get the string so it would start at the beginning of the block so would get junk data.  This change has also been pushed to the Regripper2.8 repo as well

wschaeferB/autopsy,wschaeferB/autopsy,wschaeferB/autopsy,rcordovano/autopsy,rcordovano/autopsy,wschaeferB/autopsy,esaunders/autopsy,esaunders/autopsy,rcordovano/autopsy,rcordovano/autopsy,rcordovano/autopsy,rcordovano/autopsy,esaunders/autopsy,wschaeferB/autopsy,esaunders/autopsy,esaunders/autopsy