currently, podman system df incorrectly calculates the reclaimable storage for
volumes, using a cumulative reclaimable variable that is incremented and placed into each
report entry causing values to rise above 100%.
Switch this variables to be in the context of the loop, so it resets per volume just like the size variable does.
resolves#13516
Signed-off-by: Charlie Doern <cdoern@redhat.com>