sss_packet_grow: correctly pad packet length to 512B

https://fedorahosted.org/sssd/ticket/2059

If len % SSSSRV_PACKET_MEM_SIZE == 0 or some low number,
we can end up with totlen < len and return EINVAL.

It also does not pad the length, but usually allocates
much more memory than is desired.

len = 1024
n = 1024 % 512 + 1 = 0 + 1 = 1
totlen = 1 * 512 = 512
=> totlen < len

len = 511
n = 511 % 512 + 1 = 511 + 1
totlen = 512 * 512 = 262144
totlen is way bigger than it was supposed to be

0 files changed, 0 insertions, 0 deletions