gluster: update volume capacity info in sync job

Update the volume capacity information as part of
GlusterSyncJob. It also updates the brick
details like total space and free space as part of
refreshing Heavy Weight Data.

Change-Id: Ifd187eb59ab83c426db7e9ba48a04ae7e0bef0b9
Signed-off-by: Ramesh Nachimuthu <rnachimu@redhat.com>