fix(build): E2E coverage broken on Travis CI (#1805)

Fixes an issue with the Travis CI builds failing at the E2E tests due to
an apparent issue with the Mozilla Gecko web-driver used with Selenium.

1) Upgrades `gulp-protractor` to ensure Protractor v5> is used.
2) Removes `--firefox` option from the Travis CI Selenium
`webdriver-manager update` step.
3) Changes Protractor config to use Chrome instead of Firefox.

.travis.yml

@@ -34,7 +34,7 @@ before_install:
   - npm install protractor
   - 'export DISPLAY=:99.0'
   - 'sh -e /etc/init.d/xvfb start'
-  - 'node_modules/protractor/bin/webdriver-manager update --standalone --firefox'
+  - 'node_modules/protractor/bin/webdriver-manager update --standalone'
   - 'node_modules/protractor/bin/webdriver-manager start 2>&1 &'
   - sleep 3
 #before_script:

package.json

@@ -93,7 +93,7 @@
     "gulp-mocha": "~3.0.1",
     "gulp-ng-annotate": "~2.0.0",
     "gulp-nodemon": "~2.2.1",
-    "gulp-protractor": "^3.0.0",
+    "gulp-protractor": "^4.0.0",
     "gulp-refresh": "~1.1.0",
     "gulp-rename": "~1.2.2",
     "gulp-rev": "^7.1.2",

protractor.conf.js

@@ -7,7 +7,12 @@ var config = {
 
 if (process.env.TRAVIS) {
   config.capabilities = {
-    browserName: 'firefox'
+    // Without this setting, Travis CI would default
+    // to using Chrome anyway.
+    // NOTE: Firefox is currently not working with
+    // the Travis CI builds. For more info see:
+    // https://github.com/meanjs/mean/pull/1805
+    browserName: 'chrome'
   };
 }