chore: fix lint warnings in build files (#1931)

Removes a few unused variables and formatting warnings in the Gulp-related build files.

tools/gulp/gulpfile.ts

@@ -9,4 +9,4 @@ import './tasks/lint';
 import './tasks/release';
 import './tasks/serve';
 import './tasks/unit-test';
-import './tasks/docs';
+import './tasks/docs';

tools/gulp/tasks/e2e.ts

@@ -1,7 +1,5 @@
 import {task, watch} from 'gulp';
 import * as path from 'path';
-import gulpMerge = require('merge2');
-import gulpRunSequence = require('run-sequence');
 
 import {SOURCE_ROOT, DIST_ROOT, PROJECT_ROOT} from '../constants';
 import {
@@ -53,7 +51,7 @@ task(':e2e:done', () => process.exit(0));
 let stopE2eServer: () => void = null;
 
 /** Starts up the e2e app server. */
-task(':serve:e2eapp', serverTask(false, (stream) => { stopE2eServer = () => stream.emit('kill') }));
+task(':serve:e2eapp', serverTask(false, stream => { stopE2eServer = () => stream.emit('kill'); }));
 
 /** Terminates the e2e app server */
 task(':serve:e2eapp:stop', () => stopE2eServer());

tools/gulp/tasks/release.ts

@@ -1,5 +1,5 @@
 import {spawn} from 'child_process';
-import {existsSync, readdirSync, statSync} from 'fs';
+import {existsSync, statSync} from 'fs';
 import {task} from 'gulp';
 import gulpRunSequence = require('run-sequence');
 import path = require('path');

tools/gulp/tasks/unit-test.ts

@@ -2,7 +2,7 @@ import gulp = require('gulp');
 import path = require('path');
 import gulpMerge = require('merge2');
 
-import {PROJECT_ROOT, DIST_COMPONENTS_ROOT} from '../constants';
+import {PROJECT_ROOT} from '../constants';
 import {sequenceTask} from '../task_helpers';
 
 const karma = require('karma');