criu: fix 'criu --version'

Currently kerndat_init() runs before command line parsing and running
simple 'criu --version' command may produce something like:

Warn  (criu/kerndat.c:847): Can't load /run/criu.kdat
Error (criu/util.c:842): exited, status=3
Error (criu/util.c:842): exited, status=3
Write 4294967295 to /proc/self/loginuid failed: Operation not permittedWarn
(criu/net.c:2732): Unable to get socket network namespace
Warn  (criu/net.c:2732): Unable to get tun network namespace
Warn  (criu/sk-unix.c:213): sk unix: Unable to open a socket file:
Operation not permitted
Error (criu/net.c:3023): Unable create a network namespace: Operation not
permitted
Warn  (criu/net.c:3069): NSID isn't reported for network links
Version: 3.6
GitID: v3.6-611-g0b27d0a

Group early calls to kerndat_* and init_service_fd calls into a function
and call this function after the command line parsing is finished.

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>