cgroup: s/pids.current/pids.max

pids.current is the current number of pids, not the maximum number allowed
(which is the thing we care about, that is set by the user).
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/cgroup-props.c

@@ -479,7 +479,7 @@ static int cgp_parse_builtins(void)
 			" - \"strategy\": \"replace\"\n"
 			" - \"properties\": "
 			"[ "
-				"\"pids.current\" "
+				"\"pids.max\" "
 			"]\n"
 		"\"devices\":\n"
 			" - \"strategy\": \"replace\"\n"