fixed sys.version_info for python < 2.7

Author: vemel

src/tarantool/response.py

@@ -25,7 +25,7 @@ def __new__(cls, value):
         if isinstance(value, unicode):
             return super(field, cls).__new__(cls, value.encode("utf-8", "replace"))
 
-        if sys.version_info.major < 3 and isinstance(value, str):
+        if sys.version_info[0] < 3 and isinstance(value, str):
             return super(field, cls).__new__(cls, value)
 
         if isinstance(value, (bytearray, bytes)):
@@ -57,7 +57,7 @@ def __int__(self):
             raise ValueError("Unable to cast field to int: length must be 4 or 8 bytes, field length is %d"%len(self))
 
 
-    if sys.version_info.major > 2:
+    if sys.version_info[0] > 2:
         def __str__(self):
             '''\
             Cast filed to str