Cleanup: Clarify the number meanings of string length.

Cleanup: Clarify the number meanings of string length.

Hi,

This patch clarifies the number meanings of string length in the function
cgroup_get_uid_gid_from_procfs(). This is recreated based on Igawa-san's
patch for the latest code.

* Reference
  Igawa-san's patch
  http://sourceforge.net/mailarchive/message.php?msg_name=20090515.085922.109268324.igawa%40mxs.nes.nec.co.jp

Signed-off-by: Masayuki Igawa <igawa@mxs.nes.nec.co.jp>
Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>