features/quota: use disk usage instead of file-sizes.
features/quota: use disk usage instead of file-sizes.

Signed-off-by: Raghavendra G <raghavendra@gluster.com>
Signed-off-by: Anand Avati <avati@gluster.com>

BUG: 2760 (Quota: stripe volume not showing the quota size properly)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2760

Kaushikbv/Gluster,Kaushikbv/Gluster,Kaushikbv/Gluster