Merge into PreviewTree lists only a single entry with list_files

[Justyn Butler]

Working with test_merge_into_preview in test_transform.py as a reference (bzr 1.17). This makes it easier to explain.

This test merges a Working Tree into a PreviewTree.

If the test is modified so that the work_tree has multiple files created at the beginning then the resulting "final_tree" contains only a single entry when checked via list_files, and it seems to be the first entry added - regardless of what modifications are made to the Preview Tree prior to merging.

UPDATE: Actually retrieving multiple file contents from the final_tree works so I think the tree is being created correctly. Perhaps it is only listing the entries that does not work.