Change to using TDB_INCOMPATIBLE_HASH (the jenkins hash) on all

Change to using TDB_INCOMPATIBLE_HASH (the jenkins hash) on all
TDB_CLEAR_IF_FIRST tdb's. For tdb's like gencache where we open
without CLEAR_IF_FIRST and then with CLEAR_IF_FIRST if corrupt
this is still safe to use as if opening an existing tdb the new
hash will be ignored - it's only used on creating a new tdb not
opening an old one.

Jeremy.