largefiles: directly use repo.vfs.join

The 'repo.join' method is about to be deprecated.

hgext/largefiles/lfutil.py

@@ -202,7 +202,7 b' def storepath(repo, hash, forcelocal=Fal'
     file with the given hash.'''
     if not forcelocal and repo.shared():
         return repo.vfs.reljoin(repo.sharedpath, longname, hash)
-    return repo.join(longname, hash)
+    return repo.vfs.join(longname, hash)
 
 def findstorepath(repo, hash):
     '''Search through the local store path(s) to find the file for the given