gluster: Changed the type of numeric fields to long

Changed the type fo numeric fields in class
GlusterVolumeTaskStatusDetail.
This is required because numeric fields in status might be holding
bigger values and we need long to hold these values.

Change-Id: I5c1ade59e328bfcc1440ba8ac410848d296a6a26
Signed-off-by: Shubhendu Tripathi <shtripat@redhat.com>