If the user configures a states_hashsize or source_nodes_hashsize value we may
not have enough memory to allocate this. This used to lock up pf, because these
allocations used M_WAITOK.
Cope with this by attempting the allocation with M_NOWAIT and falling back to
the default sizes (with M_WAITOK) if these fail.
PR: 209475
Submitted by: Fehmi Noyan Isi <fnoyanisi AT yahoo.com>
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D14367
bf56a3fe47