move: Improve resuming a move that was interrupted after the object was transferred

In cases where numcopies checks prevented the resumed move from dropping
the object from the source repository, it now relies on a log of recent
moves to replicate the behavior of the interrupted command.

Performance: Probably noticable impact, since it has to add to the log,
check the log, and remove from the log. Seems worth it to avoid this
annoying edge case. The log functions are pretty well optimised to avoid
unncessary work.

An performance improvement to make later would be to avoid cleanup doing
anything if it's not written to the log file, and has confirmed that the
log file does not contain the log line.

This commit was sponsored by Jake Vosloo on Patreon.

Annex/Locations.hs

@@ -47,6 +47,8 @@ module Annex.Locations (
 	gitAnnexFsckResultsLog,
 	gitAnnexSmudgeLog,
 	gitAnnexSmudgeLock,
+	gitAnnexMoveLog,
+	gitAnnexMoveLock,
 	gitAnnexExportDir,
 	gitAnnexExportDbDir,
 	gitAnnexExportLock,
@@ -377,6 +379,14 @@ gitAnnexSmudgeLog r = fromRawFilePath $ gitAnnexDir r P.</> "smudge.log"
 gitAnnexSmudgeLock :: Git.Repo -> FilePath
 gitAnnexSmudgeLock r = fromRawFilePath $ gitAnnexDir r P.</> "smudge.lck"
 
+{- .git/annex/move.log is used to log moves that are in progress,
+ - to better support resuming an interrupted move. -}
+gitAnnexMoveLog :: Git.Repo -> FilePath
+gitAnnexMoveLog r = fromRawFilePath $ gitAnnexDir r P.</> "move.log"
+
+gitAnnexMoveLock :: Git.Repo -> FilePath
+gitAnnexMoveLock r = fromRawFilePath $ gitAnnexDir r P.</> "move.lck"
+
 {- .git/annex/export/ is used to store information about
  - exports to special remotes. -}
 gitAnnexExportDir :: Git.Repo -> FilePath