introduce qemu_opts_create_nofail function

While id is NULL, qemu_opts_create can not fail, so ignore
errors is fine.
Signed-off-by: NDong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

qemu-option.c

@@ -780,6 +780,15 @@ QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
     return opts;
 }
 
+QemuOpts *qemu_opts_create_nofail(QemuOptsList *list)
+{
+    QemuOpts *opts;
+    Error *errp = NULL;
+    opts = qemu_opts_create(list, NULL, 0, &errp);
+    assert_no_error(errp);
+    return opts;
+}
+
 void qemu_opts_reset(QemuOptsList *list)
 {
     QemuOpts *opts, *next_opts;

qemu-option.h

@@ -133,6 +133,7 @@ int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
 QemuOpts *qemu_opts_find(QemuOptsList *list, const char *id);
 QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
                            int fail_if_exists, Error **errp);
+QemuOpts *qemu_opts_create_nofail(QemuOptsList *list);
 void qemu_opts_reset(QemuOptsList *list);
 void qemu_opts_loc_restore(QemuOpts *opts);
 int qemu_opts_set(QemuOptsList *list, const char *id,