ksconf promote at the attribute-level results in data loss

[lowell80]

The problem

Using the ksconf promote command in interactive mode sometimes fails when promoting specific keys (attributes) to another file. Instead of actual pushing the promoted content to the destination file, the content is removed from the source, never making it into the target, thus resulting in content loss.

This seems to only happen when a single attribute is being evaluated. Promoting full stanzas seems to work fine; but the user has no control over if they are presented with a stanza-level change or an attribute-level change.

Regressions here are hard to deal with automatically, given the lack of unit testing for interactive features; as noted here: #7 (comment)

Steps To Reproduce Issue

need to find a failing example

Please remember that sample configs often make problems easier to reproduce making it faster to fix the bug.

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