Merge ~smoser/cloud-init:bug/ds-identify-reset-set-f into cloud-init:master

[Scott Moser]

ds-identify: fix bug where filename expansion was left on.

The script is written to have the protection of disabling filename
expansion (set -f) and explicitly enabling expansion when needed.
However, the check_config function failed to disable it after enabling.

[Ryan Harper (raharper)]

I'll take this moment to remind ourselves that we need some unittest (and integration tests) for ds-identify.

review: Approve

diff --git a/tools/ds-identify b/tools/ds-identify
index e138d78..6f1e983 100755
--- a/tools/ds-identify
+++ b/tools/ds-identify
@@ -473,7 +473,7 @@ check_config() {
         files="$*"
     fi
     shift
-    set +f; set -- $files; set +f;
+    set +f; set -- $files; set -f;
     if [ "$1" = "$files" -a ! -f "$1" ]; then
         return 1
     fi