annex.dbdir fully working

Completes work started in e60766543f

I've verified that all the sqlite databases get stored in annex.dbdir
and are created successfully. If annex.dbdir does not exist, it will be
created; its parent directory must already exist though.

Sponsored-by: Dartmouth College's Datalad project

Annex/Perms.hs

@@ -106,13 +106,16 @@ annexFileMode = withShared $ return . go
 	go _ = stdFileMode
 	sharedmode = combineModes groupSharedModes
 
-{- Creates a directory inside the gitAnnexDir, creating any parent
- - directories up to and including the gitAnnexDir.
+{- Creates a directory inside the gitAnnexDir (or possibly the dbdir), 
+ - creating any parent directories up to and including the gitAnnexDir.
  - Makes directories with appropriate permissions. -}
 createAnnexDirectory :: RawFilePath -> Annex ()
 createAnnexDirectory dir = do
 	top <- parentDir <$> fromRepo gitAnnexDir
-	createDirectoryUnder' [top] dir createdir
+	tops <- annexDbDir <$> Annex.getGitConfig >>= return . \case
+		Nothing -> [top]
+		Just dbdir -> [top, parentDir dbdir]
+	createDirectoryUnder' tops dir createdir
   where
 	createdir p = do
 		liftIO $ R.createDirectory p