chore(travis): fix the build id on browser stack

This just improves the way BrowserStack groups the sessions.

Author: vojtajina

karma-shared.conf.js

@@ -112,7 +112,7 @@ module.exports = function(config, specificOptions) {
 
   if (process.env.TRAVIS) {
     config.transports = ['websocket', 'xhr-polling'];
-    config.browserStack.build = 'TRAVIS ' + process.env.TRAVIS_BUILD;
+    config.browserStack.build = 'TRAVIS ' + process.env.TRAVIS_BUILD_ID;
 
     // Debug logging into a file, that we print out at the end of the build.
     config.loggers.push({