Fix cover cannot be edited on copied card

[nztqa]

#1218
Remove the cover from the copied card

---

This change is 

[xet7]

@nztqa

When I tried this, card content (description, images, checklists etc) were not copied to new card anymore. Only card name was copied.

You could try to look at move card code how it does work moving everything, if something similar could be done to copy card.

[nztqa]

It works normally in my environment

[xet7]

I did copy it to different list than the original list. It did not work for me in that case.

[nztqa]

@xet7

It has nothing to do with this PR.
That is another matter.
Console log in browser.

WriteError({"code":11000,"index":0,"errmsg":"E11000 duplicate key error collection: wekan.checklists index: c2_items.$._id dup key: { : \"N685pxNPyaYax8MHi0\" }","op":{"cardId":"WAfHjMYuDGdo8cQgH","title":"list5","sort":0,"createdAt":"2017-09-25T13:21:04.253Z","items":[{"_id":"N685pxNPyaYax8MHi0","title":"one","isFinished":false,"sort":0},{"_id":"N685pxNPyaYax8MHi1","title":"two","isFinished":false,"sort":1},{"_id":"N685pxNPyaYax8MHi2","title":"three","isFinished":false,"sort":2}],"_id":"A7Pa4N6qEFJZeEZm9","userId":"uMQ4krMnjQ5W6TLzW"}})

Please try it

db.checklists.dropIndex( "index name" )

# in this case
db.checklists.dropIndex( "c2_items.$._id" )

[xet7]

@nztqa

When I don't add your pull request code, and copy card to same list, copied card cover can not be edited.

When I add your pull request, and copy card to same list, card cover image attachment is not visible at all.

I have these indexes, what should I do with these? How with mongo shell I could fix those? Could you add code to fix those previously copied cards so covers become editable, and I would not need to edit mongodb manually on mongodb shell?

> db.checklists.getIndexes()
[
	{
		"v" : 1,
		"key" : {
			"_id" : 1
		},
		"name" : "_id_",
		"ns" : "admin.checklists"
	},
	{
		"v" : 1,
		"key" : {
			"cardId" : 1,
			"createdAt" : 1
		},
		"name" : "cardId_1_createdAt_1",
		"ns" : "admin.checklists"
	}
]

Thanks! :)

[nztqa]

@xet7

There is no function to copy attached files in #1204.
Therefore, when the card cover is copied, data inconsistency has occurred.
This PR removes the card cover from the copied card and keeps the data clean.

[xet7]

Thanks for explaining! :)