LU-7187 jobstats: confine the output of jobid to single line

LU-7187 jobstats: confine the output of jobid to single line

Repalce the non-printable characters into '?' when display the
jobid via proc file, so that output of jobid will be confined
to a single line and not break the YAML indention.

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: Ic4e0e6196a13b46f20d96ccce7705c62674f2440
Reviewed-on: http://review.whamcloud.com/16593
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>