sparse: use `update_file` instead of `drop`

This is the newer, more semantic API.

Differential Revision: https://phab.mercurial-scm.org/D11190

mercurial/sparse.py

@@ -283,7 +283,7 b' def prunetemporaryincludes(repo):'
 
     # Fix dirstate
     for file in dropped:
-        dirstate.drop(file)
+        dirstate.update_file(file, p1_tracked=False, wc_tracked=False)
 
     repo.vfs.unlink(b'tempsparse')
     repo._sparsesignaturecache.clear()