*: add/cleanup initialisers

There were some (inconsequential) warnings about uninitialised use of
variables.  Also, in one case, sub-structs were mixed in initialisation,
which doesn't quite work as intended.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/bgpd/bgp_routemap.c b/bgpd/bgp_routemap.c
index be3c2ee..95f1dff 100644
--- a/bgpd/bgp_routemap.c
+++ b/bgpd/bgp_routemap.c
@@ -131,7 +131,7 @@
       void *object)
 {
   union sockunion *su;
-  union sockunion su_def = { .sa.sa_family = AF_INET,
+  union sockunion su_def = { .sin.sin_family = AF_INET,
 			     .sin.sin_addr.s_addr = INADDR_ANY };
   struct peer_group *group;
   struct peer *peer;