proc: parse -- Fix length for smaps maj/min parshing

Otherwise

 | Error (proc_parse.c:227): Can't parse: 555555554000-555555577000 r-xp 00000000 b6:d2f61 133545                  /sbin/init

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>