Update used Fedora images to version 21

Change-Id: I26a3d7d0842f9d4c5fc33350992a19f597f39b2e
diff --git a/stackrc b/stackrc
index ac79889..9960a1b 100644
--- a/stackrc
+++ b/stackrc
@@ -552,7 +552,7 @@
 if [[ "$ENABLED_SERVICES" =~ 'h-api' ]]; then
     case "$VIRT_DRIVER" in
         libvirt|ironic)
-            HEAT_CFN_IMAGE_URL=${HEAT_CFN_IMAGE_URL:-"https://download.fedoraproject.org/pub/alt/openstack/20/x86_64/Fedora-x86_64-20-20140618-sda.qcow2"}
+            HEAT_CFN_IMAGE_URL=${HEAT_CFN_IMAGE_URL:-"https://download.fedoraproject.org/pub/fedora/linux/releases/21/Cloud/Images/x86_64/Fedora-Cloud-Base-20141203-21.x86_64.qcow2"}
             IMAGE_URLS+=",$HEAT_CFN_IMAGE_URL"
             ;;
         *)
@@ -577,7 +577,7 @@
 PRECACHE_IMAGES=$(trueorfalse False $PRECACHE_IMAGES)
 if [[ "$PRECACHE_IMAGES" == "True" ]]; then
     # staging in update for nodepool
-    IMAGE_URL="https://download.fedoraproject.org/pub/alt/openstack/20/x86_64/Fedora-x86_64-20-20140618-sda.qcow2"
+    IMAGE_URL="https://download.fedoraproject.org/pub/fedora/linux/releases/21/Cloud/Images/x86_64/Fedora-Cloud-Base-20141203-21.x86_64.qcow2"
     if ! [[ "$IMAGE_URLS"  =~ "$IMAGE_URL" ]]; then
         IMAGE_URLS+=",$IMAGE_URL"
     fi