Automatic merge from submit-queue
[kubeadm] use iteration instead of recursion in function
**What this PR does / why we need it**:
before this PR, function `attemptToUpdateMasterRoleLabelsAndTaints` recursively call itself. there are some defeats in it:
1. potential stack overflow.
2. unnecessary extra `json.Marshal` calls.
3. unnecessary extra `client.Nodes().List` calls.
this PR rewrite `attemptToUpdateMasterRoleLabelsAndTaints` function, use iterate instead of recursion.
so these 3 defeats the metioned above are gone.
Signed-off-by: bruceauyeung <ouyang.qinhua@zte.com.cn>
