Description of problem:
kubelet add taint to node fail. Though api-server prompt add taint succ, indeed add fail.

Version-Release number of selected component (if applicable):
kubectl version:
Client Version: version.Info{Major:"1", Minor:"11+", GitVersion:"v1.11.0+1cdd4a1", GitCommit:"1cdd4a1", GitTreeState:"clean", BuildDate:"2018-12-17T12:20:26Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"11+", GitVersion:"v1.11.0+1cdd4a1", GitCommit:"1cdd4a1", GitTreeState:"clean", BuildDate:"2018-12-17T12:16:52Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}


How reproducible:
always

Steps to Reproduce:
1.add taint to node
#kubectl taint node ip-10-0-148-66.ec2.internal role=master:NoSchedule
node/ip-10-0-148-66.ec2.internal tainted
2.check node for taint info
#kubectl describe node ip-10-0-148-66.ec2.internal | grep -i taint
Taints: <none>
3.remove taint from node
# kubectl taint node ip-10-0-148-66.ec2.internal role:NoSchedule-
error: taint "role:NoSchedule" not found

Actual results:
1.add taint to node succ
2.the node has no taint
3.can not found taint

Expected results:
2.the node show taint correctly
3.remove taint succ

Additional info: