only set no_proxy if other proxy vars are defined

roles/kubespray-defaults/defaults/main.yaml

@@ -241,6 +241,7 @@ weave_peers: uninitialized
 
 ## Set no_proxy to all assigned cluster IPs and hostnames
 no_proxy: >-
+  {%- if http_proxy is defined or https_proxy is defined %}
   {%- if loadbalancer_apiserver is defined -%}
   {{ apiserver_loadbalancer_domain_name| default('') }},
   {{ loadbalancer_apiserver.address | default('') }},
@@ -254,11 +255,12 @@ no_proxy: >-
   {{ item }},{{ item }}.{{ dns_domain }},
   {%- endfor -%}
   127.0.0.1,localhost
+  {%- endif %}
 
 proxy_env:
   http_proxy: "{{ http_proxy| default ('') }}"
   https_proxy: "{{ https_proxy| default ('') }}"
-  no_proxy: "{{ no_proxy }}"
+  no_proxy: "{{ no_proxy| default ('') }}"
 
 # Vars for pointing to kubernetes api endpoints
 is_kube_master: "{{ inventory_hostname in groups['kube-master'] }}"