Merge branch 'en/merge-recursive-directory-rename-fixes' into next

A few glitches in the heuristic in merge-recursive to infer file
movements based on movements of other files in the same directory
have been corrected.

* en/merge-recursive-directory-rename-fixes:
  merge-recursive: fix merging a subdirectory into the root directory
  merge-recursive: clean up get_renamed_dir_portion()

diff --cc merge-recursive.c
Simple merge