cinder-volume: install qemu-img for conversions

Updates the cinder-volume element so that it installs the
qemu-img package. This is required in order to support
boot from volume conversions from Glance images (qcow2).

Change-Id: I1c6fb4692166b173092395967ffe9fe88ffdb602
Partial-bug: #1340479

elements/cinder-volume/element-deps

@@ -1,4 +1,5 @@
 cinder
 os-refresh-config
 os-svc-install
-use-ephemeral
+use-ephemeral
+pkg-map

elements/cinder-volume/install.d/cinder-source-install/74-cinder-volume

@@ -1,6 +1,9 @@
 #!/bin/bash
 set -eux
 
+# qemu-img is required when creating volumes from Glance images
+install-packages -m cinder-volume qemu_img_package
+
 os-svc-daemon -i "$CINDER_VENV_DIR" cinder-volume cinder cinder-volume "--config-dir /etc/cinder"
 
 # Ensure the loop block device is available

elements/cinder-volume/pkg-map

@@ -0,0 +1,16 @@
+{
+  "family": {
+    "redhat": {
+      "qemu_img_package": "qemu-img"
+    },
+    "debian": {
+      "qemu_img_package": "qemu-utils"
+    },
+    "suse": {
+      "qemu_img_package": "qemu-tools"
+    }
+  },
+  "default": {
+    "qemu_img_package": "qemu-img"
+  }
+}