Fix bytes<->str Python 3 mess

Author: Alexey Gadzhiev

tarantool/utils.py

@@ -62,7 +62,7 @@ class Greeting:
     # Tarantool 1.6.8-132-g82f5424 (Lua console)
     result = Greeting()
     try:
-        (product, _, tail) = str(greeting_buf)[0:63].partition(' ')
+        (product, _, tail) = greeting_buf[0:63].decode().partition(' ')
         if product.startswith("Tarantool "):
             raise Exception()
         # Parse a version string - 1.6.6-83-gc6b2129 or 1.6.7