TDataMatrixReader.decode bug when use TDecodeHintType.PURE_BARCODE

[JedrzejczykRobert]

file: ZXing.Datamatrix.DataMatrixReader
line: 126

current:

bits.Free;

shoul be:

FreeAndNil(bits);

or remove lines: 116,170,171

Bits:=nil;

    if Assigned(bits) then
      FreeAndNil(bits);