LU-2336 llog: hide the harmless log message

LU-2336 llog: hide the harmless log message

in llog_cat_add_rec, the llog_write_rec could return -ENOSPC
if the current log is full, and it will move to the next log
file, then it should not be treated as an error.

Change-Id: Ie2e203dc01572e170e9a383c63dcc670db093355
Signed-off-by: Hongchao Zhang <hongchao.zhang@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/5146
Tested-by: Hudson
Reviewed-by: Prakash Surya <surya1@llnl.gov>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>