Improve output of gluster-block info

[vbellur]

Sample output of gluster-block info is as below:

gluster-block info rep/bd1
NAME: bd1
VOLUME: rep
GBID: 4ddce603-c1cc-496e-a0ba-d4f537c26422
SIZE: 53687091200
HA: 3
PASSWORD:
BLOCK CONFIG NODE(S): 10.16.154.60 10.16.154.45 10.16.154.63

Some suggested improvements:

1. Displaying the size value in the unit it was configured (50 GiB in this case) or in a more human readable way would be nice.

2. BLOCK CONFIG NODE(S) does not seem very intuitive. A better string like "Exported Node(S)" or something else might make it more intuitive.

[pkalever]

Patch available:
https://review.gluster.org/#/c/17519/