Add support for image name end with .raw

Change-Id: If3bd42825a29755fa8e68fa5661d068c6f0019d2
diff --git a/functions b/functions
index 8968a18..f842f63 100644
--- a/functions
+++ b/functions
@@ -310,6 +310,11 @@
             disk_format=qcow2
             container_format=bare
             ;;
+        *.raw)
+            image_name=$(basename "$image" ".raw")
+            disk_format=raw
+            container_format=bare
+            ;;
         *.iso)
             image_name=$(basename "$image" ".iso")
             disk_format=iso