auc_compute_vectors(): fix AUTS resync for multiple vectors

Fix bug where AUTS was fed to each vector generation and thus each vector was
generated with the same SQN. In auc_3g_test, adjust the bug indicating test
expectations to now expect the proper results.

Depends: libosmocore change-id If943731a78089f0aac3d55245de80596d01314a4
Change-Id: I425a1d92c85896227341f565f5361c0d830ce866
diff --git a/src/auc.c b/src/auc.c
index f4d19a0..9c20db2 100644
--- a/src/auc.c
+++ b/src/auc.c
@@ -113,7 +113,9 @@
 		if (aud3g) {
 			/* 3G or 3G + 2G case */
 
-			if (auts) {
+			/* Do AUTS only for the first vector or we would use
+			 * the same SQN for each following key. */
+			if ((i == 0) && auts) {
 				DBGP("vector [%u]: resync: auts = %s\n",
 				     i, hex(auts, 14));
 				DBGP("vector [%u]: resync: rand_auts = %s\n",