Infinite volumes quota shows as 'inf'

When the volumes quota is set to -1 (either in the defaults panel or for
a specific project) in project overview it shows as "inf" instead of "No
Limit".

Change-Id: Ia6ea4ca56008168a63527ef5c32375070bc2b467
Closes-bug: 1271629
Merge "Infinite volumes quota shows as 'inf'"