> Pulling without specifying how to reconcile divergent branches is
discouraged.You can squelch this message by running one of the following
commands sometime before your next pull:
git config pull.rebase false # merge (the default strategy)
git config pull.rebase true # rebase
git config pull.ff only # fast-forward only
You can replace "git config" with "git config --global" to set a default
preference for all repositories. You can also pass --rebase, --no-rebase,
or --ff-only on the command line to override the configured default per
invocation.
メッセージから問題を探してみたら、原因は、以前にroot権限でpullを実行していたため、.gitのファイル権限が一部rootに変更されていた。
$ chown -R nginx:nginx root
これで解決