Simplify FS.free().
Simplify FS.free().

The 'exists' check is not necessary because currentSize itself checks 'exists'.
We believe that minSize will always be a Size during execution, so there's
no reason to make sure that it is with a guard.

Signed-off-by: mulhern <7b51bcf507bcd7afb72bf8663752c0ddbeb517f6@redhat.com>

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