LUDOC-102 format-options: Fixed inode ratio description. Also addressed LUDOC-49.

LUDOC-102 format-options: Fixed inode ratio description. Also addressed LUDOC-49.

Updated section 5.3 content about setting file system formatting options.
Removed obsolete note. Changed chapter title.

Signed-off-by: Linda Bebernes <linda.bebernes@intel.com>
Change-Id: Ib4368708c23d50c750c208a81d32294425a3fb2f
Reviewed-on: http://review.whamcloud.com/6847
Tested-by: Hudson
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Reviewed-by: Richard Henwood <richard.henwood@intel.com>