Staleness buffer had error in ExpiringCache

Signed-off-by: Aaron Rosenzweig <aaron@chatnbike.com>
No "fudge factor" required

It's wrong to add 10 seconds because short values (5) seconds expire immediately so they never work. Subtracting 10 seconds makes objects live longer (which was probably the original intent) but this really isn't necessary. It appears no "fudge factor" is needed.

Signed-off-by: Aaron Rosenzweig <aaron@chatnbike.com>
Merge pull request #376 from recurve/ExpiringCache

Staleness buffer had error in ExpiringCache