conditional_ace.idl: Fix undefined shift

conditional_ace.idl: Fix undefined shift

If ‘int’ is a 32‐bit type, then 1 << 31 cannot be represented in an
‘int’, and this shift will invoke undefined behaviour.

We have got away with this so far because of a Pidl bug that changed the
expression to ‘(uint32_t)1 << 31’, which is valid. But that bug is about
to be fixed.

Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>