LUDOC-193 ea_inode: Added index entries and info on ea_inode

LUDOC-193 ea_inode: Added index entries and info on ea_inode

In order to turn on or off the wide striping option, you can
specify large_xattr or ea_inode. Both parameters will enable
the wide striping feature. Using either parameter in tune2fs
or mkfs.lustre will result in "ea_inode" listed in the file
system features using dumpe2fs. Since there is some potential
confusion around these feature parameters, this patch hopes
to address this.

Added index entries to Section 5.3.3 "Setting up Lustre File System"
and Section 16.2 "Upgrading Lustre" to make information about the
wide striping (ea_inode) option to tune2fs and mkfs.lustre easier
to find.

Signed-off-by: James Nunez <james.a.nunez@intel.com>
Change-Id: Ice054cd1720ac3174889bd27eb22f19472597041
Reviewed-on: http://review.whamcloud.com/8297
Tested-by: Jenkins
Reviewed-by: Richard Henwood <richard.henwood@intel.com>