test/crit-recode: skip images with zero size

Now we have many tests with the crfail flags. When criu dump fails,
criu may create image files, but doesn't fill them.

Reported-by: Mr Jenkins
Signed-off-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/crit-recode.py

@@ -5,7 +5,7 @@ import sys
 import os
 import subprocess
 
-find = subprocess.Popen(['find', 'test/dump/', '-name', '*.img'],
+find = subprocess.Popen(['find', 'test/dump/', '-size', '+0', '-name', '*.img'],
 		stdout = subprocess.PIPE)
 
 test_pass = True