fix docs for stats to dispersion rename

[John Dickinson]

the admin guide still uses "dispersion" and needs to be updated to "stats"

[Razique Mahroua (razique)]

John,
are you reffering to the sentence :
"The primary factor driving the limitation of object size in OpenStack Object Storage is
               maintaining balance among the partitions of the ring. To maintain an even
                dispersion of disk usage throughout the cluster the obvious storage pattern
                was to simply split larger objects into smaller segments, which could then be
                glued together during a read" ?
Thanks

[Tom Fifield (fifieldt)]

This is for the old swiftstats (eg swift.openstack.org/1.3/overview_stats.html) going away and being replaced by the swift-dispersion tool (i.e. http://swift.openstack.org/admin_guide.html?highlight=dispersion).

I believe this bug was refering to the admin guide on swift.openstack.org, which has been updated already :)