remove quoting from dockerfile env. closes #1002

tests/unit/config.bats

@@ -59,7 +59,7 @@ teardown() {
 
 @test "global config (dockerfile)" {
   deploy_app dockerfile
-  run bash -c "docker inspect --format '{{ .Config.Env }}' $(< $DOKKU_ROOT/$TEST_APP/CONTAINER) | grep global_test"
+  run bash -c "dokku run $TEST_APP env | egrep '^global_test=true'"
   echo "output: "$output
   echo "status: "$status
   assert_success