Fix connectlogger nolog function

[eyoboue]

Fix #1284.
The server headers are now avalaible in nolog function.

[lamweili]

Hi, I don't understand how that fixes the issue.
Can you walk me through it?

Also, please add tests. Thanks!

[eyoboue]

I meant server response headers like Content-Type will be undefined in current nolog function.
These headers are avalaible only inside handler function at line 282.
So this never get server response content-type header:

nolog: (req, res) => {
    return /(css|javascript|image|font|svg|png|jpe?g)/i.test(res.getHeader('content-type'));
}

[lamweili]

Ok, can you add tests?

[eyoboue]

Ok, Roger that

[eyoboue]

Ok, can you add tests?

Test coverage done.

[lamweili]

Thanks, LGTM!