Fix variable length blob size offset (#651)
Fix variable length blob size offset (#651)

Refs #650
plusvic/yara,wxsBSD/yara,wxsBSD/yara,cblichmann/yara,VirusTotal/yara,jpypi/yara,plusvic/yara,plusvic/yara,cblichmann/yara,VirusTotal/yara,pombredanne/yara,tanium/yara,wxsBSD/yara,rednaga/yara,wxsBSD/yara,hillu/yara,pombredanne/yara,tanium/yara,hillu/yara,plusvic/yara,jpypi/yara,tanium/yara,pombredanne/yara,rednaga/yara,plusvic/yara,hillu/yara,pombredanne/yara,VirusTotal/yara,wxsBSD/yara,cblichmann/yara,rednaga/yara,VirusTotal/yara,pombredanne/yara,hillu/yara,cblichmann/yara,VirusTotal/yara,cblichmann/yara,hillu/yara,jpypi/yara