Change log level when chmod fails ?

[gytisgreitai]

Hi,

we have a kind of restricted nginx setup (non root both master and workers), so lua-resty-auto-ssl fails chmoding (though) the permissions are ok, and everything works):

nginx: [error] [lua] init_master.lua:56: generate_config(): auto-ssl: failed to create letsencrypt dir permissions: Executing command failed: chmod 777 /etc/resty-auto-ssl/letsencrypt: chmod: /etc/resty-auto-ssl/letsencrypt: Operation not permitted

IMHO this could be changed to warn only:

• 777 is a bit of overkill (but I understand the simplicity)
• If this failed, it does not mean that lets encrypt will actually fail

Would you accept a simple PR? Or you think that it's ok as it is?