Using no proxy option to skip wget and curl proxy settings in config

When end users specify proxy settings in config file for wget /etc/wgetrc:
http_proxy = http://...
or for curl ${HOME}/.curlrc:
proxy = http://...

Using `http_proxy="" wget' can not skip the proxy setting in the
config files, also it can skip proxy settings in env viriables.

In order to skip proxy setting in both env and config file, we pass
--no-proxy option for wget, and --noproxy '*' for curl.

Fixes bug #1224836

Change-Id: I2b25aeca9edf2ce4525fb1db325e5e24c18b4d55
diff --git a/functions b/functions
index 83826f9..fb2f3a3 100644
--- a/functions
+++ b/functions
@@ -1484,7 +1484,7 @@
 function wait_for_service() {
     local timeout=$1
     local url=$2
-    timeout $timeout sh -c "while ! http_proxy= https_proxy= curl -s $url >/dev/null; do sleep 1; done"
+    timeout $timeout sh -c "while ! curl --noproxy '*' -s $url >/dev/null; do sleep 1; done"
 }