viced-h_Enumerate_r-fix-20060301

viced-h_Enumerate_r-fix-20060301

In h_Enumerate_r it is possible that the host may be released by the
called procedure.  Therefore, we must preserve the pointer to host->next
before the call and hold the host it points to in order to ensure that
it does not disappear out from under us.  This ensures that although
the H_LOCK can be dropped during the procedure and the host list can
be rearranged we won't miss more than a handful of hosts during the
enumeration.