graft: get the editor later

We don't use it in that function, so I would rather have it close to the return.

mercurial/cmd_impls/graft.py

@@ -46,8 +46,6 def _process_args(ui, repo, *revs, **opt
 
     cmdutil.resolve_commit_options(ui, opts)
 
-    editor = cmdutil.getcommiteditor(editform=b'graft', **opts)
-
     cmdutil.check_at_most_one_arg(opts, 'abort', 'stop', 'continue')
 
     cont = False
@@ -220,6 +218,7 def _process_args(ui, repo, *revs, **opt
         if not revs:
             return "ERROR", None, None
 
+    editor = cmdutil.getcommiteditor(editform=b'graft', **opts)
     dry_run = bool(opts.get("dry_run"))
     tool = opts.get('tool', b'')
     return "GRAFT", graftstate, (statedata, revs, editor, cont, dry_run, tool)