r13258: Fix the talloc heirachy for ldb_tdb.

r13258: Fix the talloc heirachy for ldb_tdb.

In the return value res->msgs, msgs was not a child of res, in the
indexed path.  Instead, it hung directly off the ldb, which was
sometimes a long-term context.

Also remove unused parameters.

Found by --leak-report-full

Andrew Bartlett
(This used to be commit 29cb5af827c459758997c80dca034d471bb92449)