fix calico_version wrong get (#3694)

the ':' makes wrong return of calico_version after the calicoctl downloaded && before the cluster is up

roles/kubernetes/preinstall/tasks/0020-verify-settings.yml

@@ -137,7 +137,7 @@
     - facts
 
 - name: "Get current version of calico cluster version"
-  shell: "{{ bin_dir }}/calicoctl version  | grep 'Cluster Version' | awk '{ print $3}'"
+  shell: "{{ bin_dir }}/calicoctl version  | grep 'Cluster Version:' | awk '{ print $3}'"
   register: calico_version_on_server
   run_once: yes
   delegate_to: "{{ groups['kube-master'][0] }}"