pycriu: Dont produce zombies

When running criu_dump() with zero pid (self dump) a zombie
from the library is left underneath the running processes
and this zombie is thus written into the images.
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

lib/py/criu.py

@@ -113,6 +113,9 @@ class _criu_comm_bin(_criu_comm):
 					os._exit(0)
 			else:
 				exec_criu()
+		else:
+			if daemon:
+				os.waitpid(p, 0)
 
 		css[0].close()
 		self.swrk = struct.unpack('i', css[1].recv(4))[0]