r8609: Fix for bugid #2889. I think the problem is that the top 16 bits of the "serve...

r8609: Fix for bugid #2889. I think the problem is that the top 16 bits of the "server state" field must be
non-zero. As we're using the 32 bit field as an offset then normally this field
will be zero. W2K3 fills this field with a counter enumerating the number of
SMBsearch calls on this directory - starting at 1. Add back the 1<<31 bit flag
DPTR_MASK to ensure this is non-zero - with better checks on use.
Jeremy.
(This used to be commit 6415657942c49ea51d4e4f4ee2189c7d70b9c5fa)