Log Message:
Update perfuse package. Change log since previous version:

Use reclaim2 to fix reclaim/lookup race conditions

The PUFFS reclaim operation had a race condition with lookups: we could
be asked to lookup a node, then to reclaim it before lookup completion.

At lookup completion, we would then create a leaked node.

Enter the PUFFS reclaim2 operation, which features a nlookup argument.

That let us count how many lookups are pending and avoid the above
described scenario. It also makes the codes simplier.

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Fix directory filehandle usage with libufse. Fix lookup count
libfuse does not use filehandle the same way for directories and other
objects. As a result, filehandles obtained by OPENDIR should not be
sent on non-directory related operations like READ/WRITE/GETATTR...

While there, fix the lookup count sent to the FORGET operation, which
led to leaked nodes.