Fix indentation of closing braces

[ryuslash]

The ‘nginx-indent-block’ function would get confused by braces in comments. Here is an example of how indentation could go wrong:

server {
    # some comment with {
    # ...
    }

After this change the example is correctly indented:

server {
    # some comment with {
    # ...
}

[ajc]

Thank you very much for the fix!

It looks good, though I'm a week away from being able to properly assess this and make a new release, so please hold tight.