test qgraph.c: Fix segs due to out of scope default

The test uses the trick:
   if (!opts) {
     opts = &(QOSGraph...Options) { };
   }

  in a couple of places, however the temporary created
by the &() {}  goes out of scope at the bottom of the if,
and results in a seg or assert when opts-> fields are
used (on fedora 30's gcc 9).

Fixes: fc281c802022cb3a73a5
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190405184037.16799-1-dgilbert@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/libqos/qgraph.c

diff --git a/tests/libqos/qgraph.c b/tests/libqos/qgraph.c
index 122efc1..b149caa 100644
--- a/tests/libqos/qgraph.c
+++ b/tests/libqos/qgraph.c
@@ -77,6 +77,7 @@
 {
     char *key;
     QOSGraphEdgeList *list = g_hash_table_lookup(edge_table, source);
+    QOSGraphEdgeOptions def_opts = { };
 
     if (!list) {
         list = g_new0(QOSGraphEdgeList, 1);
@@ -85,7 +86,7 @@
     }
 
     if (!opts) {
-        opts = &(QOSGraphEdgeOptions) { };
+        opts = &def_opts;
     }
 
     QOSGraphEdge *edge = g_new0(QOSGraphEdge, 1);
@@ -590,9 +591,10 @@
 {
     QOSGraphNode *node;
     char *test_name = g_strdup_printf("%s-tests/%s", interface, name);;
+    QOSGraphTestOptions def_opts = { };
 
     if (!opts) {
-        opts = &(QOSGraphTestOptions) { };
+        opts = &def_opts;
     }
     node = create_node(test_name, QNODE_TEST);
     node->u.test.function = test_func;