Added NoneType error check for convert_to_list

[snapshotleisure]

Adding NoneType check to fix the issue #1508. The convert_to_list is not checking for NoneType which occurs when someone is using the tdnf module to perform a update_cache or upgrade command, as this does not populate the name argument which is used to create the pkglist.

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[sshedi]

Hi @snapshotleisure,
Yes, issue is valid and I'm willing to take a fix for this. The proposed fix works but I would prefer this version instead.

@@ -289,6 +289,9 @@
     """Convert nested list into flat list"""
     flat_list = []

+    if not input_list:
+        return flat_list
+
     for sublist in input_list:
         if not isinstance(sublist, list):
             flat_list.append(sublist)

Can you please send another patch please?

[snapshotleisure]

Hi @sshedi, no worries have tested your recommended fix and it works well, I have created pull request #1518

[vmwclabot]

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