lib:tdb: Add missing overflow check for num_values in pytdb.c

lib:tdb: Add missing overflow check for num_values in pytdb.c

Error: INTEGER_OVERFLOW (CWE-190):
tdb-1.4.10/pytdb.c:401: cast_overflow: Truncation due to cast operation on "num_values" from 64 to 32 bits.
tdb-1.4.10/pytdb.c:401: overflow_sink: "num_values", which might have overflowed, is passed to "tdb_storev(self->ctx, key, values, num_values, flag)".
  399|           }
  400|
  401|->         ret = tdb_storev(self->ctx, key, values, num_values, flag);
  402|           free(values);
  403|           PyErr_TDB_ERROR_IS_ERR_RAISE(ret, self->ctx);

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>