Fix bugs in bindresvport_sa() changes

In svctcp_create() and svcudp_bufcreate(), set sa->sa_len on platforms
where that field exists, so that a subsequent call to socklen() will
return the correct result.

To make the code more self-evidently correct, zero the entire struct
sockaddr_storage object, using the memset(&ss, 0, sizeof(ss)) idiom.

https://github.com/krb5/krb5/commit/158a551b14b017d232066c4a053dc608d87fa172
Author: Tom Yu <tlyu@mit.edu>
Commit: 158a551b14b017d232066c4a053dc608d87fa172
Branch: master
 src/lib/rpc/svc_tcp.c |    5 ++++-
 src/lib/rpc/svc_udp.c |    5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)