pidl: Fix unsigned integer comparison warning

pidl: Fix unsigned integer comparison warning

bin/default/librpc/gen_ndr/py_wkssvc.c:27344:33: warning:
comparison of integer expressions of different signedness: ‘long int’
and ‘long long unsigned int’ [-Wsign-compare] <--[gcc]
    if (test_var < 0 || test_var > uint_max) {
                                 ^

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Thu Dec 13 05:00:20 CET 2018 on sn-devel-144