LU-13857 obdclass: Add white space to output valid YAML.

LU-13857 obdclass: Add white space to output valid YAML.

YAML needs a white space after the colon(:) between a pair of key and
value. In this case, if the integer is large enough, it will leave no
white space. So insert the white space forcefully.

Change-Id: I366b5399cc293a66a70ea6084c6a5fa30a58813b
Signed-off-by: Lei Feng <flei@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/41709
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: Maloo <maloo@whamcloud.com>