s3-auth Change type of num_sids to uint32_t

s3-auth Change type of num_sids to uint32_t

size_t is overkill here, and in struct security_token in the num_sids
is uint32_t.

This includes a change to the prototype of add_sid_to_array()
and add_sid_to_array_unique(), which has had a number of
consequnetial changes as I try to sort out all the callers using
a pointer to the number of sids.

Andrew Bartlett

Signed-off-by: Andrew Tridgell <tridge@samba.org>