Remove workaround for kubeadm upgrade (#6478)

https://github.com/kubernetes/kubeadm/issues/1498 was closed

roles/kubernetes/master/tasks/kubeadm-upgrade.yml

@@ -27,8 +27,6 @@
   failed_when: kubeadm_upgrade.rc != 0 and "field is immutable" not in kubeadm_upgrade.stderr
   notify: Master | restart kubelet
 
-# FIXME: https://github.com/kubernetes/kubeadm/issues/1498 remove stdout_lines
-# check after issue is fixed
 - name: kubeadm | Upgrade other masters
   command: >-
     timeout -k 600s 600s
@@ -44,7 +42,6 @@
   failed_when:
     - kubeadm_upgrade.rc != 0
     - '"field is immutable" not in kubeadm_upgrade.stderr'
-    - kubeadm_upgrade.stdout_lines | length > 1
   notify: Master | restart kubelet
 
 - name: kubeadm | clean kubectl cache to refresh api types