qdev: Don't abort() in case globals can't be set

It would be much better if we didn't terminate QEMU inside
device_post_init(), but at least exiting cleanly is better than aborting
and dumping core.

Before this patch:

    $ qemu-system-x86_64 -global cpu.xxx=y
    qemu-system-x86_64: Property '.xxx' not found
    Aborted (core dumped)

After this patch:

    $ qemu-system-x86_64 -global cpu.xxx=y
    qemu-system-x86_64: Property '.xxx' not found
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-By: NIgor Mammedov <imammedo@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

hw/core/qdev.c

@@ -957,7 +957,13 @@ static void device_initfn(Object *obj)
 
 static void device_post_init(Object *obj)
 {
-    qdev_prop_set_globals(DEVICE(obj), &error_abort);
+    Error *err = NULL;
+    qdev_prop_set_globals(DEVICE(obj), &err);
+    if (err) {
+        qerror_report_err(err);
+        error_free(err);
+        exit(EXIT_FAILURE);
+    }
 }
 
 /* Unlink device from bus and free the structure.  */