Ignore vmdk files as well as other image types

Change-Id: I012b21181f1e54a1e4a3707b0fdf8c0afa6222c2
diff --git a/.gitignore b/.gitignore
index a5a17c2..e813cff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,7 @@
 doc/files
 doc/build
 files/*.gz
+files/*.vmdk
 files/*.rpm
 files/*.rpm.*
 files/*.qcow2