system.repo call curl with proxy env.

Change-Id: If5a8d56cc950ad0730ac728da20875a5c92bc194

linux/system/repo.sls

@@ -112,13 +112,14 @@ linux_repo_{{ name }}_key:
 #}
 {%- elif repo.key_url|default(False) and grains['saltversioninfo'] < [2017, 7] and not repo.key_url.startswith('salt://') %}
 
+{% set _export_proxy = "export no_proxy=${no_proxy:-" + system.proxy.get('noproxy', []) |join(',') + "} http_proxy=${http_proxy:-" + system.proxy.get('http', '') + "} https_proxy=${https_proxy:-" + system.proxy.get('https', '') +"}; " %}
 
 linux_repo_{{ name }}_key:
   cmd.run:
-    - name: "curl -sL {{ repo.key_url }} | apt-key add -"
+    - name: "{{ _export_proxy }} curl -sL {{ repo.key_url }} | apt-key add -"
     {%- if not grains.get('kitchen-test') %}
     {# omitted from tests, as behaves inconsistently across CI/platforms #}
-    - unless: "apt-key finger --with-colons | grep -qF $(curl -sL {{ repo.key_url }} | gpg --with-fingerprint --with-colons | grep -E '^fpr')"
+    - unless: "apt-key finger --with-colons | grep -qF $({{ _export_proxy }} curl -sL {{ repo.key_url }} | gpg --with-fingerprint --with-colons | grep -E '^fpr')"
     {%- endif %}
     - require_in:
     {%- if repo.get('default', False) %}