rename confusing function

The index.lck file is not a lock file. Kept the historical name for now as
changing it would be work.

Annex/Branch.hs

@@ -351,18 +351,18 @@ forceUpdateIndex branchref = do
 {- Checks if the index needs to be updated. -}
 needUpdateIndex :: Git.Ref -> Annex Bool
 needUpdateIndex branchref = do
-	lock <- fromRepo gitAnnexIndexLock
-	lockref <- Git.Ref . firstLine <$>
-		liftIO (catchDefaultIO "" $ readFileStrict lock)
-	return (lockref /= branchref)
+	f <- fromRepo gitAnnexIndexStatus
+	committedref <- Git.Ref . firstLine <$>
+		liftIO (catchDefaultIO "" $ readFileStrict f)
+	return (committedref /= branchref)
 
 {- Record that the branch's index has been updated to correspond to a
  - given ref of the branch. -}
 setIndexSha :: Git.Ref -> Annex ()
 setIndexSha ref = do
-	lock <- fromRepo gitAnnexIndexLock
-	liftIO $ writeFile lock $ show ref ++ "\n"
-	setAnnexPerm lock
+	f <- fromRepo gitAnnexIndexStatus
+	liftIO $ writeFile f $ show ref ++ "\n"
+	setAnnexPerm f
 
 {- Stages the journal into the index and returns an action that will
  - clean up the staged journal files, which should only be run once

Locations.hs

@@ -35,7 +35,7 @@ module Locations (
 	gitAnnexJournalDir,
 	gitAnnexJournalLock,
 	gitAnnexIndex,
-	gitAnnexIndexLock,
+	gitAnnexIndexStatus,
 	gitAnnexIgnoredRefs,
 	gitAnnexPidFile,
 	gitAnnexDaemonStatusFile,
@@ -223,10 +223,12 @@ gitAnnexJournalLock r = gitAnnexDir r </> "journal.lck"
 gitAnnexIndex :: Git.Repo -> FilePath
 gitAnnexIndex r = gitAnnexDir r </> "index"
 
-{- Lock file for .git/annex/index. Not to be confused with git's 
- - index.lock. -}
-gitAnnexIndexLock :: Git.Repo -> FilePath
-gitAnnexIndexLock r = gitAnnexDir r </> "index.lck"
+{- Holds the ref of the git-annex branch that the index was last updated to.
+ -
+ - The .lck in the name is a historical accident; this is not used as a
+ - lock. -}
+gitAnnexIndexStatus :: Git.Repo -> FilePath
+gitAnnexIndexStatus r = gitAnnexDir r </> "index.lck"
 
 {- List of refs that should not be merged into the git-annex branch. -}
 gitAnnexIgnoredRefs :: Git.Repo -> FilePath