wendelin: make wendelin format checksum compatible with python2 and 3

bt5/erp5_wendelin/SkinTemplateItem/portal_skins/erp5_wendelin/Base_numpyToWendelinData.py

@@ -11,5 +11,5 @@ io.seek(0)
 npy_data = io.read()
 io.close()
 
-crc = struct.pack('<i', binascii.crc32(npy_data))
+crc = struct.pack('<I', binascii.crc32(npy_data) & 0xffffffff)
 return b''.join([MAGIC_HEADER, crc, npy_data])

bt5/erp5_wendelin/SkinTemplateItem/portal_skins/erp5_wendelin/Base_wendelinDataToNumpy.py

@@ -16,8 +16,8 @@ major, minor = map(ord, magic_str[-2:]) #python2
 assert major == 0 and minor == 1
 
 # verify crc32 checksum
-checksum = struct.unpack('<i', data[MAGIC_LEN:HEADER_LEN])[0]
-assert checksum == binascii.crc32(data[HEADER_LEN:])
+checksum = struct.unpack('<I', data[MAGIC_LEN:HEADER_LEN])[0]
+assert checksum == binascii.crc32(data[HEADER_LEN:]) & 0xffffffff
 io = StringIO()
 io.write(data[HEADER_LEN:])
 io.seek(0)