CLEANUP: peers: Remove useless test on peer variable in peer_trace()

A useless test on peer variable was reported by cppcheck in peer_trace().

This patch should fix the issue #1165.
diff --git a/src/peers.c b/src/peers.c
index 94ef22e..5cd2f74 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -443,7 +443,7 @@
 			const struct peer *peer = a2;
 			struct peers *peers = NULL;
 
-			if (peer && peer->appctx) {
+			if (peer->appctx) {
 				struct stream_interface *si;
 
 				si = peer->appctx->owner;
@@ -456,8 +456,7 @@
 
 			if (peers)
 				chunk_appendf(&trace_buf, " %s", peers->local->id);
-			if (peer)
-				chunk_appendf(&trace_buf, " -> %s", peer->id);
+			chunk_appendf(&trace_buf, " -> %s", peer->id);
 		}
 
 		if (a3) {