b9173 - fd cleanups

[Amos Jeffries]

http://www.squid-cache.org/Versions/v3/HEAD/changesets/b9173.patch
Alex, were there any bugs or potential bugs related to this fix? It 
rings a small bell in the back of my mind.

Amos
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Please use Squid 2.7.STABLE4 or 3.0.STABLE8