use proxy settings specified in http_proxy, HTTP_PROXY, http_proxy_user, HTTP_PROXY_USER, http_proxy_pass, HTTP_PROXY_PASS (if any of these are set in the environment).
Merge branch 'use_proxy_if_set_in_env'

* use_proxy_if_set_in_env:
  use proxy settings specified in http_proxy, HTTP_PROXY, http_proxy_user, HTTP_PROXY_USER, http_proxy_pass, HTTP_PROXY_PASS (if any of these are set in the environment).

Conflicts:
	lib/cupertino/provisioning_portal/agent.rb