test(e2e): Use current directory so e2e test won't complain about directory not exists (#2693)

* Use current directory so e2e test wont complain about directory not exists

* change .gitignore

* Only take screenshot when run on travis

* remove log

Author: tinayuangao

.gitignore

@@ -4,6 +4,7 @@
 /dist
 /tmp
 /deploy
+/screenshots
 
 # dependencies
 /node_modules

e2e/screenshot.ts

@@ -3,7 +3,7 @@ import * as gulp from 'gulp';
 import * as path from 'path';
 import {browser} from 'protractor';
 
-const OUTPUT_DIR = '/tmp/angular-material2-build/screenshots/';
+const OUTPUT_DIR = './screenshots/';
 
 let currentJasmineSpecName = '';
 
@@ -53,5 +53,7 @@ export class Screenshot {
 }
 
 export function screenshot(id: string) {
-  return new Screenshot(id);
+  if (process.env['TRAVIS']) {
+    return new Screenshot(id);
+  }
 }