replace use of cirros 0.3.0 with 0.3.1
cirros 0.3.1 images have several significant improvements over 0.3.0, including:
* newer kernel (3.2.0-25.40)
* support for more filesystems (vfat, iso9660)
* support for configdrive (config-drive-v2) as a datasource
* acpi reboot/shutdown
* curl with https support (previously there was no way to get https urls)
Change-Id: Idd7bef0cebb941f77d1cead9dc990fa0b03ff46b
diff --git a/stack.sh b/stack.sh
index 331743f..62f533d 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1215,8 +1215,9 @@
# Upload an image to glance.
#
# The default image is cirros, a small testing image which lets you login as **root**
-# cirros also uses ``cloud-init``, supporting login via keypair and sending scripts as
-# userdata. See https://help.ubuntu.com/community/CloudInit for more on cloud-init
+# cirros has a ``cloud-init`` analog supporting login via keypair and sending
+# scripts as userdata.
+# See https://help.ubuntu.com/community/CloudInit for more on cloud-init
#
# Override ``IMAGE_URLS`` with a comma-separated list of UEC images.
# * **oneiric**: http://uec-images.ubuntu.com/oneiric/current/oneiric-server-cloudimg-amd64.tar.gz