LU-694 config: make 'jobid_var' global

LU-694 config: make 'jobid_var' global

This patch makes the global parameter able to accept
string value, and move the 'jobid_var' from the llite
folder into the lustre proc root /proc/fs/lustre.

Signed-off-by: Niu Yawei <niu@whamcloud.com>
Change-Id: Ibaac19d2f29f8631d4717c6b0f82853cff64fc96
Reviewed-on: http://review.whamcloud.com/2785
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>