git: add a missing reset_copy keyword argument to dirstate.set_tracked()

Since nothing else in hgext/git supports copies yet, the best I can do is avoid
TypeError: set_tracked() got an unexpected keyword argument 'reset_copy'.

hgext/git/dirstate.py

@@ -330,7 +330,8 b' class gitdirstate:'
         # TODO: figure out a strategy for saving index backups.
         pass
 
-    def set_tracked(self, f):
+    def set_tracked(self, f, reset_copy=False):
+        # TODO: support copies and reset_copy=True
         uf = pycompat.fsdecode(f)
         if uf in self.git.index:
             return False