Fix a -Wdeprecated-declarations warning.

[kaworu]

This patch remove the declaration as the variable is unused.

Before this PR we get:

  CXX(target) Release/obj.target/udev/udev.o
../udev.cc: In static member function ‘static void Monitor::on_handle_event(uv_poll_t*, int, int)’:
../udev.cc:62:18: warning: ‘v8::TryCatch::TryCatch()’ is deprecated: Use isolate version [-Wdeprecated-declarations]
         TryCatch tc;
                  ^

System info for the context:

% node --version
v6.10.3
% npm --version
5.0.3
% lsb_release -d                                                                                                                       
Description:    Ubuntu 16.04.2 LTS

[cheery]

Hi @kAworu and thanks for the patches.

Are the exceptions correctly logged and handled despite removing this? Or are they handled in the first place? Could you check that out?

[kaworu]

@cheery my pleasure for the patches, thank you for this module! We are using it @Netoxygen on Raspberry Pi to detect some type of devices connected with great success.

About this PR, I don't see any changes in behaviour (exceptions are not logged nor handled) before and after the patch. I also tried to replace it by a Nan::TryCatch but without any visible impact either, so finally choose to just remove it instead.

I feel I must be testing it incorrectly, here is an example script I used:

var util = require("util");
var udev = require("./udev.js");

var monitor = udev.monitor();
monitor.on('add', function (device) {
    console.log(device.DEVPATH + " added");
    throw new Error("Trycatch?");
});

Does this example looks like a good test case to you? If not, can you provide an example or hints? If yes, what is the expected behaviour?

[cheery]

If the error doesn't appear like it appears in this case:

setTimeout(function(){
    console.log("timeout");
    throw new Error("Trycatch?");
}, 1);

Then we got a bug there. It's not a big thing but it ensures you get some message into the log if there's a problem.

To be consistent, it may be good idea to check from some other library how they do this. It might even be a common usage pattern of Local that we are missing here.

All right.. I merge this.