Fix signing failure when no entry to convert to store

zip -d doesn't work when no entry names specified. So if the list of
entry is empty, just skip calling zip -d.

Bug: 218438888

Test: th
Change-Id: Ie4419b9d6fdc2780255c6f12f9f4d35e5c0a7b26

tools/releasetools/common.py

@@ -2818,6 +2818,9 @@ def ZipDelete(zip_filename, entries):
   """
   if isinstance(entries, str):
     entries = [entries]
+  # If list is empty, nothing to do
+  if not entries:
+    return
   cmd = ["zip", "-d", zip_filename] + entries
   RunAndCheckOutput(cmd)