test: import pycriu by its right name

Otherwise one library will be imported twice by two different names: py
and pycriu, because pycriu is used in the library.

https://github.com/checkpoint-restore/criu/issues/495Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

test/crit-recode.py

 #!/bin/env python2
 
-import py as pycriu
+import pycriu
 import sys
 import os
 import subprocess