dom0/core: add missing "cleanup_dispvms" file (#648)

dom0/aux-tools/cleanup_dispvms

@@ -0,0 +1,16 @@
+#!/usr/bin/python
+
+from qubes.qubes import QubesVmCollection
+
+def main():
+    qvm_collection = QubesVmCollection()
+    qvm_collection.lock_db_for_writing()
+    qvm_collection.load()
+    for vm in qvm_collection.values():
+        if vm.is_disposablevm() and not vm.is_running():
+            qvm_collection.pop(vm.qid)
+    qvm_collection.save()
+    qvm_collection.unlock_db()
+
+
+main()