Fix : sort variables fetched from env list

In bionic, when exporting env variables, the env list displays
variables in unsorted format.
While fetching we are getting 'https_proxy' before 'http_proxy'
which is failing in comparison to our expected values[1].
This patch sorts the variables fetched from env.

[1] http://logs.openstack.org/30/643130/3/check/devstack-unit-tests/effbf7a/job-output.txt.gz#_2019-03-13_23_12_35_465026

Change-Id: Ie504eabf0d3fec1b97bc711e2702c06bcf75d158
diff --git a/tests/test_functions.sh b/tests/test_functions.sh
index adf20cd..08143d2 100755
--- a/tests/test_functions.sh
+++ b/tests/test_functions.sh
@@ -272,7 +272,7 @@
 
     export_proxy_variables
     expected=$(echo -e "http_proxy=$http_proxy\nhttps_proxy=$https_proxy\nno_proxy=$no_proxy")
-    results=$(env | egrep '(http(s)?|no)_proxy=')
+    results=$(env | egrep '(http(s)?|no)_proxy=' | sort)
     if [[ $expected = $results ]]; then
         passed "OK: Proxy variables are exported when proxy variables are set"
     else