Implements "nginx reload" handler

[ghost]

For better high-availability, in some case it's more friendly to reload instead of restart.

That patch make possible the usage of notify: nginx reload.

[ghost]

@dctremblay why not directly replace restart with reload? Is there a known case where restart is preferable to reload?

Also, as a side note: you introduce here a handler that isn't used in the role. What is your goal here, use that handler in another role? I think it's better practice, in ansible, not to rely on handlers from another role. If you need "nginx reload" in another role, add it to that role directly.

[ghost]

@hsoft If I do edit the pull request in order to completely replace restart with reload, would it be merged ?

[ghost]

If you tell me that you've looked at nginx's doc and that you're confident that we won't break stuff by doing so, yes.