v6: fix migrate of unlocked file

After commit b2bafdb2fc the test suite
threw up a failure migrating unlocked files.

I'm not clear how that commit broke it (presumably by inAnnex reporting
the right information now), but the actual problem is plain:
The inodecache for the worktree file is generated, but then the file is
replaced with a copy (unncessarily unless annex.link is set, but the
code always does so) and so linkToAnnex/linkAnnex then fails because it
notices the inode cache is not valid.

This commit was sponsored by Jake Vosloo on Patreon.

Command/ReKey.hs

@@ -87,7 +87,6 @@ linkKey file oldkey newkey = ifM (isJust <$> isAnnexLink file)
 		oldobj <- calcRepo (gitAnnexLocation oldkey)
 		isJust <$> linkOrCopy' (return True) newkey oldobj tmp Nothing
 	, do
-		ic <- withTSDelta (liftIO . genInodeCache file)
 	 	{- The file being rekeyed is itself an unlocked file, so if
 		 - it's linked to the old key, that link must be broken. -}
 		oldobj <- calcRepo (gitAnnexLocation oldkey)
@@ -99,6 +98,7 @@ linkKey file oldkey newkey = ifM (isJust <$> isAnnexLink file)
 			oldic <- withTSDelta (liftIO . genInodeCache oldobj)
 			whenM (isUnmodified oldkey oldobj) $
 				Database.Keys.addInodeCaches oldkey (catMaybes [oldic])
+		ic <- withTSDelta (liftIO . genInodeCache file)
 		case v of
 			Left e -> do
 				warning (show e)