[PATCH] Subtract sizes of added-then-rejected entries while loading ufs cache index

Hi there,

    Before SMP changes, the ufs code was incorrectly ignoring the size
of loaded-but-not-yet-validated entries, leading to cache disk
overflows. After SMP changes, the ufs code was not subtracting sizes of
loaded-but-then-rejected entries, leading to bogus "Disk space over
limit" warnings. With this patch, we correctly account for both kinds of
entries.

The patch also removes some code duplication and fixes counts.objcount
maintenance.

TODO: Do not enter the validation loop in storeCleanup unless running
with -S. The loop does nothing useful when storeCleanupDoubleCheck() is
not called. I am not planning to work on that though so please feel free
to tackle it.

Thank you,

Alex.