Fix the build error when "./absolute webpack" intermittently

[nadongguri]

If you run "./absolute webpack" many times, you would see the error comming

$ ./absolute webpack
[14:04:32] Requiring external module ts-node/register
[14:04:32] Using gulpfile /absolute/gulpfile.ts
[14:04:32] Starting 'webpack'...
ts-loader: Using typescript@2.6.1 and /absolute/tsconfig.json

stream.js:74
throw er; // Unhandled stream error in pipe.
^
Error: absolute/node_modules/@types/supertest/index.d.ts
(27,20): error TS2304: Cannot find name 'RegExp' /absolute/node_modules/@types/supertest/index.d.ts

....

I think this error is due to the line in push_service_worker.ts.

/// <reference path="../../node_modules/typescript/lib/lib.webworker.d.ts"/>

When I removed that line or modifying from /// to // made no command error.
I'm not sure why that leads to the build error but if owners can agree of my experimental test,
I will upload the patch.

[nadongguri]

@haeungun, is that line is really required?

[haeungun]

If that causes an error, you can delete it.
We can load an interface without a reference tag.

[nadongguri]

@haeungun, thanks to your reply.
@GarlicB, you were checking this issue at MOGACKO, would you fix this issue ASAP? I can't make PR in the company.

[GarlicB]

@nadongguri OK. soon i'll make PR about that.