Only use heat image where support

Glance will reject images that it doesn't understand, and only certain drivers can
use qcow2 images.  This means for systems without qcow2 support, devstack
will fail to run until this change is merged.

Change-Id: Ic92815f3d32880e987456c0428953dddaa81c94c
diff --git a/stackrc b/stackrc
index 95ee779..822403e 100644
--- a/stackrc
+++ b/stackrc
@@ -342,10 +342,15 @@
 
 # Use 64bit fedora image if heat is enabled
 if [[ "$ENABLED_SERVICES" =~ 'h-api' ]]; then
-    HEAT_CFN_IMAGE_URL=${HEAT_CFN_IMAGE_URL:-"https://dl.fedoraproject.org/pub/fedora/linux/releases/20/Images/x86_64/Fedora-x86_64-20-20131211.1-sda.qcow2"}
-    IMAGE_URLS+=",$HEAT_CFN_IMAGE_URL"
+    case "$VIRT_DRIVER" in
+        libvirt|baremetal|ironic)
+            HEAT_CFN_IMAGE_URL=${HEAT_CFN_IMAGE_URL:-"https://dl.fedoraproject.org/pub/fedora/linux/releases/20/Images/x86_64/Fedora-x86_64-20-20131211.1-sda.qcow2"}
+            IMAGE_URLS+=",$HEAT_CFN_IMAGE_URL"
+            ;;
+        *)
+            ;;
+    esac
 fi
-
 # Staging Area for New Images, have them here for at least 24hrs for nodepool
 # to cache them otherwise the failure rates in the gate are too high
 PRECACHE_IMAGES=$(trueorfalse False $PRECACHE_IMAGES)